Chromium (III) catalyst systems with activator-supports

ABSTRACT

Methods for preparing supported chromium catalysts containing a chromium (III) compound and an activator-support are disclosed. These supported chromium catalysts can be used in catalyst compositions for the polymerization of olefins to produce polymers having low levels of long chain branching, and with greater sensitivity to the presence of hydrogen during polymerization.

BACKGROUND OF THE INVENTION

Polyolefins such as high density polyethylene (HDPE) homopolymer andlinear low density polyethylene (LLDPE) copolymer can be produced usingvarious combinations of catalyst systems and polymerization processes.Traditional chromium-based catalyst systems can produce olefin polymershaving, for example, good extrusion processibility and polymer meltstrength, typically due to their broad molecular weight distribution(MWD). In some end-use applications, it can be beneficial for the olefinpolymer also to have low levels of long chain branching. Moreover, itcan be beneficial for the catalyst system employed to have a highcatalytic activity for olefin polymerization, particularly in thepresence of relatively high levels of co-catalyst, as well as a greatersensitivity to hydrogen to enable a broader range of polymer melt indexand molecular weight. Accordingly, it is to these ends that the presentinvention is directed.

SUMMARY OF THE INVENTION

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the detaileddescription. This summary is not intended to identify required oressential features of the claimed subject matter. Nor is this summaryintended to be used to limit the scope of the claimed subject matter.

The present invention generally relates to new catalyst compositions,methods for preparing catalyst compositions, methods for using thecatalyst compositions to polymerize olefins, the polymer resins producedusing such catalyst compositions, and articles produced using thesepolymer resins. In particular, the present invention relates tosupported chromium-based catalyst systems, and to chromium compoundssupported on activator-supports. Catalyst compositions of the presentinvention which contain these supported chromium catalysts can be usedto produce, for example, ethylene-based homopolymers and copolymers. Aparticular catalyst composition disclosed herein can comprise asupported chromium catalyst comprising a chromium (III) compound, and anactivator-support comprising a solid oxide treated with anelectron-withdrawing anion; and a co-catalyst. In some aspects, theco-catalyst can comprise an organoaluminum compound.

Processes for producing the supported chromium catalyst also aredescribed herein. For example, the process can comprise (i) combining achromium (III) compound with an activator-support comprising a solidoxide treated with an electron-withdrawing anion to form a mixture; and(ii) subjecting the mixture to a non-oxidizing atmosphere at a peaktemperature to produce the supported chromium catalyst.

The present invention also contemplates and encompasses olefinpolymerization processes. Such processes can comprise contacting acatalyst composition with an olefin monomer and optionally an olefincomonomer in a polymerization reactor system under polymerizationconditions to produce an olefin polymer. Generally, the catalystcomposition employed can comprise any of the chromium (III) compounds(or derivatives thereof), any of the activator-supports, and any of theco-catalysts disclosed herein. For example, activator-supports which canbe utilized in the catalyst compositions and/or polymerization processescan include a fluorided solid oxide and/or a sulfated solid oxide.

Polymers produced from the polymerization of olefins, resulting inhomopolymers, copolymers, etc., can be used to produce various articlesof manufacture. A representative and non-limiting example of an olefinpolymer (e.g., an ethylene copolymer) consistent with aspects of thisinvention can be characterized as having the following properties: a Mwin a range from about 400,000 to about 900,000 g/mol (or from about300,000 to about 1,000,000 g/mol); a ratio of Mw/Mn of greater than orequal to about 70 (or greater than or equal to about 35, or greater thanor equal to about 50, or greater than or equal to about 90); and arelaxation time of less than or equal to about 100 sec (or less than orequal to about 70 sec, or less than or equal to about 120 sec). Anotherrepresentative and non-limiting ethylene-based polymer described hereincan have a Mw in a range from about 400,000 to about 900,000 g/mol (orfrom about 300,000 to about 1,000,000 g/mol); a ratio of Mw/Mn ofgreater than or equal to about 70 (or greater than or equal to about 35,or greater than or equal to about 50, or greater than or equal to about90); and less than or equal to about 0.001 LCB per 1000 total carbonatoms (or less than or equal to about 0.005 LCB per 1000 total carbonatoms, or less than or equal to about 0.002 LCB per 1000 total carbonatoms). Yet another representative and non-limiting ethylene-basedpolymer described herein can have a HLMI of less than or equal to about1 g/10 min (or less than or equal to about 5 g/10 min, or less than orequal to about 10 g/10 min); a ratio of Mw/Mn of greater than or equalto about 70 (or greater than or equal to about 35, or greater than orequal to about 50, or greater than or equal to about 90); and less thanor equal to about 0.001 LCB per 1000 total carbon atoms (or less than orequal to about 0.005 LCB per 1000 total carbon atoms, or less than orequal to about 0.002 LCB per 1000 total carbon atoms).

Both the foregoing summary and the following detailed descriptionprovide examples and are explanatory only. Accordingly, the foregoingsummary and the following detailed description should not be consideredto be restrictive. Further, features or variations may be provided inaddition to those set forth herein. For example, certain aspects andembodiments may be directed to various feature combinations andsub-combinations described in the detailed description.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 presents a plot of catalyst activity versus the final (peak)treatment temperature for chromium (III) catalyst systems containingfluorided silica-coated alumina and prepared in inert or reducingatmospheres.

FIG. 2 presents a plot of the molecular weight distributions of thepolymers of Example 5 and three commercial resins made from Cr(VI)catalyst systems.

FIG. 3 presents a plot of the molecular weight distributions of polymersproduced using different activator-supports.

FIG. 4 presents a plot of the molecular weight distributions of polymersproduced using Cr(AcAc)₃ supported on fluorided silica-coated alumina,which was treated at 450° C. using inert or reducing atmospheres.

FIG. 5 presents a plot of the weight-average molecular weight (Mw)versus the final (peak) treatment temperature for the catalyst system ofExample 25, in which the treatment temperature was varied, using inertor reducing atmospheres.

FIG. 6 presents a plot of the molecular weight distributions of polymersmade using Cr(AcAc)₃ supported on fluorided silica-coated alumina, whichwas treated in nitrogen at various temperatures.

FIG. 7 presents a plot of the logarithm of the zero-shear viscosityversus the logarithm of weight-average molecular weight (Mw) for certainpolymers in Table I and Table II, using different activator-supports.

FIG. 8 presents a plot of the logarithm of zero-shear viscosity versusthe logarithm of weight-average molecular weight (Mw) for polymersproduced using different chromium loadings and using different peaktreatment temperatures.

FIG. 9 presents a plot of the molecular weight distributions of thepolymers of certain examples shown in Table III, produced usingCr(AcAc)₃ supported on fluorided silica-coated alumina, and usingdifferent amounts of hydrogen during polymerization.

FIG. 10 presents a plot of the molecular weight distributions ofpolymers made using Cr(AcAc)₃ on fluorided silica-coated alumina usingdifferent co-catalysts.

FIG. 11 presents a plot of the catalyst activity of Cr(AcAc)₃ onfluorided silica-coated alumina versus the amount of triisobutylaluminum(TIBA) co-catalyst.

FIG. 12 presents a plot of the molecular weight distributions ofpolymers produced using different amounts of TIBA co-catalyst.

FIG. 13 presents a plot of the molecular weight distributions ofpolymers produced using different chromium (III) compounds depositedonto fluorided silica-coated alumina.

FIG. 14 presents a plot of the molecular weight distribution and shortchain branch (SCB) distribution of an ethylene/1-hexene copolymerproducing using Cr(AcAc)₃ on fluorided silica-coated alumina.

FIG. 15 presents a plot of the molecular weight distributions ofpolymers produced using a combination of Cr(AcAc)₃ and a metallocenecompound on fluorided silica-coated alumina, at a range of differentzirconium:chromium molar ratios.

DEFINITIONS

To define more clearly the terms used herein, the following definitionsare provided. Unless otherwise indicated, the following definitions areapplicable to this disclosure. If a term is used in this disclosure butis not specifically defined herein, the definition from the IUPACCompendium of Chemical Terminology, 2nd Ed (1997) can be applied, aslong as that definition does not conflict with any other disclosure ordefinition applied herein, or render indefinite or non-enabled any claimto which that definition is applied. To the extent that any definitionor usage provided by any document incorporated herein by referenceconflicts with the definition or usage provided herein, the definitionor usage provided herein controls.

While compositions and methods are described herein in terms of“comprising” various components or steps, the compositions and methodscan also “consist essentially of” or “consist of” the various componentsor steps, unless stated otherwise. For example, a catalyst compositionconsistent with aspects of the present invention can comprise;alternatively, can consist essentially of; or alternatively, can consistof; (i) a supported chromium catalyst, and (ii) a co-catalyst.

The terms “a,” “an,” “the,” etc., are intended to include pluralalternatives, e.g., at least one, unless otherwise specified. Forinstance, the disclosure of “an activator-support” or “a chromium (III)compound” is meant to encompass one, or mixtures or combinations of morethan one, activator-support or chromium (III) compound, respectively,unless otherwise specified.

Generally, groups of elements are indicated using the numbering schemeindicated in the version of the periodic table of elements published inChemical and Engineering News, 63(5), 27, 1985. In some instances, agroup of elements can be indicated using a common name assigned to thegroup; for example, alkali metals for Group 1 elements, alkaline earthmetals for Group 2 elements, transition metals for Group 3-12 elements,and halogens or halides for Group 17 elements.

For any particular compound disclosed herein, the general structure orname presented is also intended to encompass all structural isomers,conformational isomers, and stereoisomers that can arise from aparticular set of substituents, unless indicated otherwise. Thus, ageneral reference to a compound includes all structural isomers unlessexplicitly indicated otherwise; e.g., a general reference to pentaneincludes n-pentane, 2-methyl-butane, and 2,2-dimethylpropane, while ageneral reference to a butyl group includes an n-butyl group, asec-butyl group, an iso-butyl group, and a tert-butyl group.Additionally, the reference to a general structure or name encompassesall enantiomers, diastereomers, and other optical isomers whether inenantiomeric or racemic forms, as well as mixtures of stereoisomers, asthe context permits or requires. For any particular formula or name thatis presented, any general formula or name presented also encompasses allconformational isomers, regioisomers, and stereoisomers that can arisefrom a particular set of substituents.

The term “substituted” when used to describe a group, for example, whenreferring to a substituted analog of a particular group, is intended todescribe any non-hydrogen moiety that formally replaces a hydrogen inthat group, and is intended to be non-limiting. A group or groups canalso be referred to herein as “unsubstituted” or by equivalent termssuch as “non-substituted,” which refers to the original group in which anon-hydrogen moiety does not replace a hydrogen within that group.Unless otherwise specified, “substituted” is intended to be non-limitingand include inorganic substituents or organic substituents as understoodby one of ordinary skill in the art.

The term “hydrocarbon” whenever used in this specification and claimsrefers to a compound containing only carbon and hydrogen. Otheridentifiers can be utilized to indicate the presence of particulargroups in the hydrocarbon (e.g., halogenated hydrocarbon indicates thepresence of one or more halogen atoms replacing an equivalent number ofhydrogen atoms in the hydrocarbon). The term “hydrocarbyl group” is usedherein in accordance with the definition specified by IUPAC: a univalentgroup formed by removing a hydrogen atom from a hydrocarbon (that is, agroup containing only carbon and hydrogen). Non-limiting examples ofhydrocarbyl groups can have from 1 to 36 carbon atoms, or from 1 to 18carbon atoms (e.g., C₁ to C₁₈ hydrocarbyl groups, C₁ to C₈ hydrocarbylgroups, etc.), and can include alkyl, alkenyl, aryl, and aralkyl groups,amongst other groups.

The term “polymer” is used herein generically to include olefinhomopolymers, copolymers, terpolymers, and so forth. A copolymer isderived from an olefin monomer and one olefin comonomer, while aterpolymer is derived from an olefin monomer and two olefin comonomers.Accordingly, “polymer” encompasses copolymers, terpolymers, etc.,derived from any olefin monomer and comonomer(s) disclosed herein.Similarly, an ethylene polymer would include ethylene homopolymers,ethylene copolymers, ethylene terpolymers, and the like. As an example,an olefin copolymer, such as an ethylene copolymer, can be derived fromethylene and a comonomer, such as 1-butene, 1-hexene, or 1-octene. Ifthe monomer and comonomer were ethylene and 1-hexene, respectively, theresulting polymer can be categorized an as ethylene/1-hexene copolymer.

In like manner, the scope of the term “polymerization” includeshomopolymerization, copolymerization, terpolymerization, etc. Therefore,a copolymerization process can involve contacting one olefin monomer(e.g., ethylene) and one olefin comonomer (e.g., 1-hexene) to produce acopolymer.

The term “co-catalyst” is used generally herein to refer to compoundssuch as aluminoxane compounds, organoboron compounds, organoaluminumcompounds, and the like, that can constitute one component of a catalystcomposition, when used, for example, in addition to a support (e.g., anactivator-support) and a chromium compound. The term “co-catalyst” isused regardless of the actual function of the compound or any chemicalmechanism by which the compound may operate.

The terms “catalyst composition,” “catalyst mixture,” “catalyst system,”and the like, do not depend upon the actual product or compositionresulting from the contact or reaction of the initial components of thedisclosed or claimed catalyst composition/mixture/system, the nature ofthe active catalytic site, or the fate of the co-catalyst,activator-support, or chromium (III) compound, after combining thesecomponents. Therefore, the terms “catalyst composition,” “catalystmixture,” “catalyst system,” and the like, encompass the initialstarting components of the composition, as well as whatever product(s)may result from contacting these initial starting components, and thisis inclusive of both heterogeneous and homogenous catalyst systems orcompositions. The terms “catalyst composition,” “catalyst mixture,”“catalyst system,” and the like, can be used interchangeably throughoutthis disclosure.

The term “contact product” is used herein to describe compositionswherein the components are contacted together in any order, in anymanner, and for any length of time. For example, the components can becontacted by blending or mixing. Further, contacting of any componentcan occur in the presence or absence of any other component of thecompositions described herein. Combining additional materials orcomponents can be done by any suitable method. Further, the term“contact product” includes mixtures, blends, solutions, slurries,reaction products, and the like, or combinations thereof. Although“contact product” can include reaction products, it is not required forthe respective components to react with one another. Similarly, the term“contacting” is used herein to refer to materials which can be blended,mixed, slurried, dissolved, reacted, treated, or otherwise contacted insome other manner.

Although any methods, devices, and materials similar or equivalent tothose described herein can be used in the practice or testing of theinvention, the typical methods, devices and materials are hereindescribed.

All publications and patents mentioned herein are incorporated herein byreference for the purpose of describing and disclosing, for example, theconstructs and methodologies that are described in the publications,which might be used in connection with the presently describedinvention. The publications discussed throughout the text are providedsolely for their disclosure prior to the filing date of the presentapplication. Nothing herein is to be construed as an admission that theinventors are not entitled to antedate such disclosure by virtue ofprior invention.

Applicants disclose several types of ranges in the present invention.When Applicants disclose or claim a range of any type, Applicants'intent is to disclose or claim individually each possible number thatsuch a range could reasonably encompass, including end points of therange as well as any sub-ranges and combinations of sub-rangesencompassed therein. For example, by a disclosure that the peakmolecular weight (Mp) can be in a range from about 30,000 to about130,000 g/mol, Applicants intend to recite that the Mp can be anymolecular weight in the range and, for example, can be equal to about30,000, about 40,000, about 50,000, about 60,000, about 70,000, about80,000, about 90,000, about 100,000, about 110,000, about 120,000, orabout 130,000 g/mol. Additionally, the Mp can be within any range fromabout 30,000 to about 130,000 (for example, from about 40,000 to about80,000), and this also includes any combination of ranges between about30,000 and about 130,000 (for example, the Mp can be in a range fromabout 30,000 to about 75,000, or from about 90,000 to about 125,000).Likewise, all other ranges disclosed herein should be interpretedsimilarly.

Applicants reserve the right to proviso out or exclude any individualmembers of any such group, including any sub-ranges or combinations ofsub-ranges within the group, that can be claimed according to a range orin any similar manner, if for any reason Applicants choose to claim lessthan the full measure of the disclosure, for example, to account for areference that Applicants may be unaware of at the time of the filing ofthe application. Further, Applicants reserve the right to proviso out orexclude any individual substituents, analogs, compounds, ligands,structures, or groups thereof, or any members of a claimed group, if forany reason Applicants choose to claim less than the full measure of thedisclosure, for example, to account for a reference that Applicants maybe unaware of at the time of the filing of the application.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed generally to supported chromiumcatalysts, methods for preparing the supported catalysts and catalystcompositions containing the supported catalysts, methods for using thecatalyst compositions to polymerize olefins, the polymer resins producedusing such catalyst compositions, and articles produced using thesepolymer resins. In particular, the present invention relates tosupported chromium catalysts containing a chromium (III) compound and anactivator-support comprising a solid oxide treated with anelectron-withdrawing anion, and to catalyst compositions employing thesesupported chromium catalysts.

Chromium (III) Compounds

Chromium-based catalysts and catalyst systems encompassed herein cancomprise a chromium (III) compound (or trivalent chromium compound), ora derivative thereof. For instance, the chromium (III) compound cancomprise a chromium (III) 1,3-diketone compound, or a derivativethereof. In some aspects, the chromium (III) compound is a compoundcontaining only chromium, carbon, hydrogen, and oxygen atoms.Accordingly, in other aspects, the chromium (III) compound is not achromium oxide or other chromium compound that does not contain a carbonatom.

In an aspect, the chromium (III) compound can comprise chromium (III)formate, chromium (III) acetate, chromium (III) propionate, chromium(III) butyrate, chromium (III) pentanoate, chromium (III) neopentanoate,chromium (III) hexanoate, chromium (III) 2-ethylhexanoate, chromium(III) benzoate, chromium (III) naphthenate, chromium (III) oleate,chromium (III) oxalate, chromium (III) acetylacetonate, chromium (III)stearate, chromium (III) laurate, a derivative thereof, or anycombination thereof. For instance, the chromium (III) compound cancomprise chromium (III) formate; alternatively, chromium (III) acetate;alternatively, chromium (III) propionate; alternatively, chromium (III)butyrate; alternatively, chromium (III) pentanoate; alternatively,chromium (III) neopentanoate; alternatively, chromium (III) hexanoate;alternatively, chromium (III) 2-ethylhexanoate; alternatively, chromium(III) benzoate; alternatively, chromium (III) naphthenate;alternatively, chromium (III) oleate; alternatively, chromium (III)oxalate; alternatively, chromium (III) acetylacetonate; alternatively,chromium (III) stearate; alternatively, chromium (III) laurate; oralternatively, a derivative of any of these chromium (III) compounds.

In another aspect, the chromium (III) compound can comprise chromium(III) 1,3-butanedionate, chromium (III) 2,4-hexanedionate, chromium(III) 2,4-heptanedionate, chromium (III) 2,4-octanedionate, chromium(III) 3,5-octanedionate, chromium (III) benzoylacetonate, chromium (III)1,3-diphenyl-1,3-propanedionate, chromium (III)2-methyl-1,3-butanedionate, chromium (III) 2-ethyl-1,3-butanedionate,chromium (III) 2-phenyl-1,3-butanedionate, chromium (III)1,2,3-triphenyl-1,3-propanedionate, chromium (III)2,2,6,6-tetramethylheptanedionate, a derivative thereof, or anycombination thereof. For instance, the chromium (III) compound cancomprise chromium (III) 1,3-butanedionate; alternatively, chromium (III)2,4-hexanedionate; alternatively, chromium (III) 2,4-heptanedionate;alternatively, chromium (III) 2,4-octanedionate; alternatively, chromium(III) 3,5-octanedionate; alternatively, chromium (III) benzoylacetonate;alternatively, chromium (III) 1,3-diphenyl-1,3-propanedionate;alternatively, chromium (III) 2-methyl-1,3-butanedionate; alternatively,chromium (III) 2-ethyl-1,3-butanedionate; alternatively, chromium (III)2-phenyl-1,3-butanedionate; alternatively, chromium (III)1,2,3-triphenyl-1,3-propanedionate; alternatively, chromium (III)2,2,6,6-tetramethylheptanedionate; or alternatively, a derivative of anyof these chromium (III) compounds.

In yet another aspect, the chromium (III) compound can comprise chromium(III) acetylacetonate, chromium (III) 2-ethylhexanoate, chromium (III)naphthenate, a derivative of, or any combination thereof. In stillanother aspect, the chromium (III) compound can comprise chromium (III)acetylacetonate, or a derivative thereof.

Activator-Supports

The present invention encompasses various catalyst compositionscontaining an activator-support. In one aspect, the activator-supportcan comprise a solid oxide treated with an electron-withdrawing anion.Alternatively, in another aspect, the activator-support can comprise asolid oxide treated with an electron-withdrawing anion, the solid oxidecontaining a Lewis-acidic metal ion. Non-limiting examples of suitableactivator-supports are disclosed in, for instance, U.S. Pat. Nos.7,294,599, 7,601,665, 7,884,163, and 8,309,485, which are incorporatedherein by reference in their entirety.

The solid oxide can encompass oxide materials such as alumina, “mixedoxides” thereof such as silica-alumina, coatings of one oxide onanother, and combinations and mixtures thereof. The mixed oxides such assilica-alumina can be single or multiple chemical phases with more thanone metal combined with oxygen to form the solid oxide. Examples ofmixed oxides that can be used to form an activator-support, eithersingly or in combination, can include, but are not limited to,silica-alumina, silica-titania, silica-zirconia, alumina-titania,alumina-zirconia, zinc-aluminate, alumina-boria, silica-boria,aluminophosphate-silica, titania-zirconia, and the like. The solid oxideused herein also can encompass oxide materials such as silica-coatedalumina, as described in U.S. Pat. No. 7,884,163.

Accordingly, in one aspect, the solid oxide can comprise silica,alumina, silica-alumina, silica-coated alumina, aluminum phosphate,aluminophosphate, heteropolytungstate, titania, silica-titania,zirconia, silica-zirconia, magnesia, boria, zinc oxide, any mixed oxidethereof, or any combination thereof. In another aspect, the solid oxidecan comprise alumina, silica-alumina, silica-coated alumina, aluminumphosphate, aluminophosphate, heteropolytungstate, titania,silica-titania, zirconia, silica-zirconia, magnesia, boria, or zincoxide, as well as any mixed oxide thereof, or any mixture thereof. Inanother aspect, the solid oxide can comprise silica, alumina, titania,zirconia, magnesia, boria, zinc oxide, any mixed oxide thereof, or anycombination thereof. In yet another aspect, the solid oxide can comprisesilica-alumina, silica-coated alumina, silica-titania, silica-zirconia,alumina-boria, or any combination thereof. In still another aspect, thesolid oxide can comprise alumina, silica-alumina, silica-coated alumina,or any mixture thereof; alternatively, alumina; alternatively,silica-alumina; or alternatively, silica-coated alumina.

The silica-alumina or silica-coated alumina solid oxide materials whichcan be used can have an silica content from about 5 to about 95% byweight. In one aspect, the silica content of these solid oxides can befrom about 10 to about 80%, or from about 20% to about 70%, silica byweight. In another aspect, such materials can have silica contentsranging from about 15% to about 60%, or from about 25% to about 50%,silica by weight. The solid oxides contemplated herein can have anysuitable surface area, pore volume, and particle size, as would berecognized by those of skill in the art.

The electron-withdrawing component used to treat the solid oxide can beany component that increases the Lewis or Brønsted acidity of the solidoxide upon treatment (as compared to the solid oxide that is not treatedwith at least one electron-withdrawing anion). According to one aspect,the electron-withdrawing component can be an electron-withdrawing anionderived from a salt, an acid, or other compound, such as a volatileorganic compound, that serves as a source or precursor for that anion.Examples of electron-withdrawing anions can include, but are not limitedto, sulfate, bisulfate, fluoride, chloride, bromide, iodide,fluorosulfate, fluoroborate, phosphate, fluorophosphate,trifluoroacetate, triflate, fluorozirconate, flluorotitanate,phospho-tungstate, tungstate, molybdate, and the like, includingmixtures and combinations thereof. In addition, other ionic or non-ioniccompounds that serve as sources for these electron-withdrawing anionsalso can be employed. It is contemplated that the electron-withdrawinganion can be, or can comprise, fluoride, chloride, bromide, phosphate,triflate, bisulfate, or sulfate, and the like, or any combinationthereof, in some aspects provided herein. In other aspects, theelectron-withdrawing anion can comprise sulfate, bisulfate, fluoride,chloride, bromide, iodide, fluorosulfate, fluoroborate, phosphate,fluorophosphate, trifluoroacetate, triflate, fluorozirconate,fluorotitanate, and the like, or combinations thereof. Yet, in otheraspects, the electron-withdrawing anion can comprise fluoride and/orsulfate, or alternatively, fluoride and/or chloride.

The activator-support generally can contain from about 1 to about 25 wt.% of the electron-withdrawing anion, based on the weight of theactivator-support. In particular aspects provided herein, theactivator-support can contain from about 1 to about 20 wt. %, from about2 to about 20 wt. %, from about 3 to about 20 wt. %, from about 2 toabout 15 wt. %, from about 3 to about 15 wt. %, from about 3 to about 12wt. %, or from about 4 to about 10 wt. %, of the electron-withdrawinganion, based on the total weight of the activator-support.

In an aspect, the supported catalyst can comprise an activator-supportcomprising fluorided alumina, chlorided alumina, bromided alumina,sulfated alumina, fluorided silica-alumina, chlorided silica-alumina,bromided silica-alumina, sulfated silica-alumina, fluoridedsilica-zirconia, chlorided silica-zirconia, bromided silica-zirconia,sulfated silica-zirconia, fluorided silica-titania, fluoridedsilica-coated alumina, sulfated silica-coated alumina, phosphatedsilica-coated alumina, and the like, as well as any mixture orcombination thereof. In another aspect, the activator-support employedin the supported catalyst can be, or can comprise, a fluorided solidoxide and/or a sulfated solid oxide, non-limiting examples of which caninclude fluorided alumina, sulfated alumina, fluorided silica-alumina,sulfated silica-alumina, fluorided silica-zirconia, fluoridedsilica-coated alumina, sulfated silica-coated alumina, and the like, aswell as combinations thereof. In yet another aspect, theactivator-support can comprise fluorided alumina; alternatively,chlorided alumina; alternatively, sulfated alumina; alternatively,fluorided silica-alumina; alternatively, sulfated silica-alumina;alternatively, fluorided silica-zirconia; alternatively, chloridedsilica-zirconia; alternatively, sulfated silica-coated alumina;alternatively, fluorided silica-coated alumina; or alternatively,chlorided/fluorided silica-coated alumina.

Various processes can be used to form activator-supports useful in thepresent invention. Methods of contacting the solid oxide with theelectron-withdrawing component, suitable electron withdrawing componentsand addition amounts, and various calcining procedures and conditionsare disclosed in, for example, U.S. Pat. Nos. 6,107,230, 6,165,929,6,294,494, 6,300,271, 6,316,553, 6,355,594, 6,376,415, 6,388,017,6,391,816, 6,395,666, 6,524,987, 6,548,441, 6,548,442, 6,576,583,6,613,712, 6,632,894, 6,667,274, 6,750,302, 7,294,599, 7,601,665,7,884,163, and 8,309,485, which are incorporated herein by reference intheir entirety. Other suitable processes and procedures for preparingactivator-supports (e.g., fluorided solid oxides, sulfated solid oxides,etc.) are well known to those of skill in the art.

Co-Catalysts

The catalyst compositions disclosed herein generally contain aco-catalyst. In some aspects, the co-catalyst can comprise a metalhydrocarbyl compound, examples of which include non-halide metalhydrocarbyl compounds, metal hydrocarbyl halide compounds, non-halidemetal alkyl compounds, metal alkyl halide compounds, and so forth, andin which the metal can be any suitable metal, often a group 13 metal.Hence, the metal can be boron or aluminum in certain aspects of thisinvention, and the co-catalyst can comprise a boron hydrocarbyl oralkyl, or an aluminum hydrocarbyl or alkyl, as well as combinationsthereof.

In one aspect, the co-catalyst can comprise an aluminoxane compound, anorganoaluminum compound, or an organoboron compound, and this includescombinations of more than co-catalyst compound. Representative andnon-limiting examples of aluminoxanes include methylaluminoxane,modified methylaluminoxane, ethylaluminoxane, n-propylaluminoxane,iso-propylaluminoxane, n-butylaluminoxane, t-butylaluminoxane,sec-butylaluminoxane, iso-butylaluminoxane, 1-pentylaluminoxane,2-pentylaluminoxane, 3-pentylaluminoxane, isopentylaluminoxane,neopentylaluminoxane, and the like, or any combination thereof.Representative and non-limiting examples of organoaluminums includetrimethylaluminum, triethylaluminum, tri-n-propylaluminum,tri-n-butylaluminum, triisobutylaluminum, tri-n-hexylaluminum,tri-n-octylaluminum, diisobutylaluminum hydride, diethylaluminumethoxide, diethylaluminum chloride, and the like, or any combinationthereof. Representative and non-limiting examples of organoboronsinclude tri-n-butyl borane, tripropylborane, triethylborane, and thelike, or any combination thereof. Co-catalysts that can be used in thecatalyst compositions of this invention are not limited to theco-catalysts described above. Other suitable co-catalysts are well knownto those of skill in the art including, for example, those disclosed inU.S. Pat. Nos. 3,242,099, 4,794,096, 4,808,561, 5,576,259, 5,807,938,5,919,983, 7,294,599 7,601,665, 7,884,163, 8,114,946, and 8,309,485,which are incorporated herein by reference in their entirety.

Olefin Monomers

Unsaturated reactants that can be employed with catalyst compositionsand polymerization processes of this invention typically can includeolefin compounds having from 2 to 30 carbon atoms per molecule andhaving at least one olefinic double bond. This invention encompasseshomopolymerization processes using a single olefin such as ethylene orpropylene, as well as copolymerization, terpolymerization, etc.,reactions using an olefin monomer with at least one different olefiniccompound. For example, the resultant ethylene copolymers, terpolymers,etc., generally can contain a major amount of ethylene (>50 molepercent) and a minor amount of comonomer (<50 mole percent), though thisis not a requirement. Comonomers that can be copolymerized with ethyleneoften can have from 3 to 20 carbon atoms, or from 3 to 10 carbon atoms,in their molecular chain.

Acyclic, cyclic, polycyclic, terminal (α), internal, linear, branched,substituted, unsubstituted, functionalized, and non-functionalizedolefins can be employed in this invention. For example, typicalunsaturated compounds that can be polymerized with the catalystcompositions of this invention can include, but are not limited to,ethylene, propylene, 1-butene, 2-butene, 3-methyl-1-butene, isobutylene,1-pentene, 2-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene,2-hexene, 3-hexene, 3-ethyl-1-hexene, 1-heptene, 2-heptene, 3-heptene,the four normal octenes (e.g., 1-octene), the four normal nonenes, thefive normal decenes, and the like, or mixtures of two or more of thesecompounds. Cyclic and bicyclic olefins, including but not limited to,cyclopentene, cyclohexene, norbornylene, norbornadiene, and the like,also can be polymerized as described herein. Styrene can also beemployed as a monomer in the present invention. In an aspect, the olefinmonomer can comprise a C₂-C₂₀ olefin; alternatively, a C₂-C₂₀alpha-olefin; alternatively, a C₂-C₁₀ olefin; alternatively, a C₂-C₁₀alpha-olefin; alternatively, the olefin monomer can comprise ethylene;or alternatively, the olefin monomer can comprise propylene.

When a copolymer (or alternatively, a terpolymer) is desired, the olefinmonomer and the olefin comonomer independently can comprise, forexample, a C₂-C₂₀ alpha-olefin. In some aspects, the olefin monomer cancomprise ethylene or propylene, which is copolymerized with at least onecomonomer (e.g., a C₂-C₂₀ alpha-olefin, a C₃-C₂₀ alpha-olefin, etc.).According to one aspect of this invention, the olefin monomer used inthe polymerization process can comprise ethylene. In this aspect,examples of suitable olefin comonomers can include, but are not limitedto, propylene, 1-butene, 2-butene, 3-methyl-1-butene, isobutylene,1-pentene, 2-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene,2-hexene, 3-ethyl-1-hexene, 1-heptene, 2-heptene, 3-heptene, 1-octene,1-decene, styrene, and the like, or combinations thereof. According toanother aspect of the present invention, the olefin monomer can compriseethylene, and the comonomer can comprise a C₃-C₁₀ alpha-olefin;alternatively, the comonomer can comprise 1-butene, 1-pentene, 1-hexene,1-octene, 1-decene, styrene, or any combination thereof; alternatively,the comonomer can comprise 1-butene, 1-hexene, 1-octene, or anycombination thereof; alternatively, the comonomer can comprise 1-butene;alternatively, the comonomer can comprise 1-hexene; or alternatively,the comonomer can comprise 1-octene.

Generally, the amount of comonomer introduced into a polymerizationreactor system to produce a copolymer can be from about 0.01 to about 50weight percent of the comonomer, based on the total weight of themonomer and comonomer. According to another aspect of the presentinvention, the amount of comonomer introduced into a polymerizationreactor system can be from about 0.01 to about 40 weight percentcomonomer, based on the total weight of the monomer and comonomer, oralternatively, from about 0.1 to about 35 weight percent comonomer, orfrom about 0.5 to about 20 weight percent comonomer.

While not intending to be bound by this theory, where branched,substituted, or functionalized olefins are used as reactants, it isbelieved that a steric hindrance can impede and/or slow thepolymerization process. Thus, branched and/or cyclic portion(s) of theolefin removed somewhat from the carbon-carbon double bond would not beexpected to hinder the reaction in the way that the same olefinsubstituents situated more proximate to the carbon-carbon double bondmight.

According to one aspect of the present invention, at least onemonomer/reactant can be ethylene (or propylene), so the polymerizationreaction can be a homopolymerization involving only ethylene (orpropylene), or a copolymerization with a different acyclic, cyclic,terminal, internal, linear, branched, substituted, or unsubstitutedolefin. In addition, the catalyst compositions of this invention can beused in the polymerization of diolefin compounds including, but notlimited to, 1,3-butadiene, isoprene, 1,4-pentadiene, and 1,5-hexadiene.

Catalyst Compositions

In some aspects, the present invention employs catalyst compositionscontaining a supported chromium catalyst comprising (a) a chromium (III)compound, or a derivative thereof, and (b) an activator-supportcomprising a solid oxide treated with an electron-withdrawing anion; anda co-catalyst (one or more than one). These catalyst compositions can beutilized to produce polyolefins—homopolymers, copolymers, and thelike—for a variety of end-use applications. Chromium (III) compounds andactivator-supports are discussed hereinabove. In aspects of the presentinvention, it is contemplated that the catalyst composition can containmore than one supported chromium catalyst. Further, additional catalyticcompounds can be employed in the catalyst compositions and/or thepolymerization processes, provided that the additional catalyticcompounds do not detract from the advantages disclosed herein.

Generally, catalyst compositions of the present invention comprise asupported chromium catalyst comprising (a) a chromium (III) compound, ora derivative thereof, and (b) an activator-support comprising a solidoxide treated with an electron-withdrawing anion; and a co-catalyst.Suitable co-catalysts, such as organoaluminum compounds, are discussedhereinabove. Thus, a catalyst composition consistent with aspects of theinvention can comprise a supported chromium catalyst comprising (orconsisting essentially of, or consisting of) chromium (III)acetylacetonate (or chromium (III) 2-ethylhexanoate, or chromium (III)naphthenate, or derivatives thereof) and sulfated alumina (or fluoridedsilica-alumina, or fluorided silica-coated alumina); andtriethylaluminum (or triisobutylaluminum). The chromium compound in thesupported chromium catalyst and resultant catalyst composition includes“a derivative thereof” to encompass situations where, for instance,during formation of the supported catalyst and/or catalyst composition,the chromium (III) compound may lose one ligand (or more ligands), andtherefore, may not be chemically the same as the initial/startingchromium (III) material used to prepare the supported catalyst. Forexample, during the formation of the catalyst system, the chromium (III)compound may lose a ligand and/or may be reduced to a chromium (II) formafter contacting a co-catalyst, such as triisobutylaluminum (TIBA).

Consistent with aspects of this invention, the weight percentage ofchromium of the chromium (III) compound, based on the weight of theactivator-support, often can be in a range from about 0.1 to about 10wt. %. For example, the weight percentage can be in a range from about0.25 to about 10 wt. % Cr, from about 0.1 to about 5 wt. % Cr, or fromabout 0.25 to about 5 wt. % Cr. In certain aspects, the weightpercentage of chromium in the chromium (III) compound, based on theweight of the activator-support, can be in a range from about 0.5 toabout 5 wt. %, from about 0.5 to about 2 wt. %, from about 0.5 to about1.5 wt. %, from about 0.75 to about 2.5 wt. %, or from about 0.75 to 1.5wt. % Cr.

In the catalyst composition, the ratio of the moles of co-catalyst(e.g., an organoaluminum compound) to the moles of chromium in thesupported catalyst typically can be in a range from about 0.1:1 to about10,000:1. More typically, the molar ratio of co-catalyst:chromium can bein a range from about 1:1 to about 1000:1, from about 1:1 to about500:1, from about 10:1 to about 1000:1, or from about 50:1 to about500:1.

Catalyst compositions of the present invention generally have a catalystactivity greater than about 500 grams of ethylene polymer (e.g.,ethylene homopolymer, ethylene copolymer, as the context requires) pergram of supported chromium catalyst per hour (abbreviated g/g/h). In anaspect, the catalyst activity can be greater than about 750, greaterthan about 850, or greater than about 1000 g/g/h. In another aspect,catalyst compositions of this invention can be characterized by having acatalyst activity greater than about 1500, greater than about 2000,greater than about 3000, greater than about 4000, or greater than about5000 g/g/h, and often can range up to about 6000-10,000 g/g/h. Theseactivities are measured under slurry polymerization conditions, with atriisobutylaluminum (TIBA) co-catalyst, using isobutane as the diluent,at a polymerization temperature of 100° C. and a reactor pressure ofabout 550 psig. Additionally, in some aspects, the activator-support canbe sulfated alumina, fluorided silica-alumina, or fluoridedsilica-coated alumina, although not limited thereto.

Unexpectedly, catalyst compositions of the present invention cantolerate much higher levels of co-catalyst than catalyst systemsemploying Cr(VI), and still maintain acceptable catalyst activity. Inone aspect, for example, catalyst compositions with a molar ratio oforganoaluminum:chromium in a range from about 10:1 to about 1000:1(e.g., 100:1) can have a catalyst activity greater than about 500 g/g/h,while in another aspect, the catalyst composition can have a catalystactivity of greater than about 750, or greater than about 1000 g/g/h.These activities are measured under slurry polymerization conditions,with an organoaluminum co-catalyst (e.g., at a TIBA:Cr molar ratio of100:1), using isobutane as the diluent, at a polymerization temperatureof 100° C. and a reactor pressure of about 550 psig.

In some aspects of this invention, the catalyst composition can comprisea supported chromium catalyst, a co-catalyst, and a metallocenecompound. The metallocene compound can be any suitable bridged and/orunbridged metallocene compound, such as disclosed in U.S. Pat. Nos.7,026,494, 7,041,617, 7,199,073, 7,226,886, 7,312,283, 7,517,939,7,619,047, 7,863,210, 7,919,639, 8,012,900, and 8,080,681, which areincorporated herein by reference in their entirety. Generally, therelative amounts of chromium (in the supported catalyst) and transitionmetal (in the metallocene compound) are not limited to any particularrange. However, in certain aspects, the molar ratio ofchromium:transition metal can be in a range from about 1:20 to about20:1, from about 1:10 to about 10:1, from about 1:5 to about 5:1, fromabout 1:4 to about 4:1, from about 1:3 to about 3:1, from about 1:2 toabout 2:1, from about 1:1.5 to about 1.5:1, or from about 1:1.2 to about1.2:1.

This invention further encompasses methods of making the disclosedcatalyst compositions, such as, for example, by contacting therespective catalyst components in any order or sequence, and moreover,also encompasses methods for making the disclosed supported chromiumcatalysts. For example, one such method of making a supported chromiumcatalyst can comprise (i) combining a chromium (III) compound with anactivator-support comprising a solid oxide treated with anelectron-withdrawing anion to form a mixture; and (ii) subjecting (e.g.,exposing, treating, etc.) the mixture to a non-oxidizing atmosphere at apeak temperature to produce the supported chromium catalyst. Chromium(III) compounds and activator-supports are discussed hereinabove.

In one aspect, step (i) comprises dry mixing the activator-support withthe chromium (III) compound, and step (ii) comprises subjecting themixture to the non-oxidizing atmosphere at a peak temperature sufficientfor at least a portion of the chromium (III) compound to sublime (orvaporize) and impregnate the activator-support. In another aspect, step(i) comprises mixing the activator-support with the chromium (III)compound in a solvent, and step (ii) comprises subjecting the mixture tothe non-oxidizing atmosphere at a peak temperature sufficient to removethe solvent. Other suitable processes and procedures for combining thechromium (III) compound and the activator-support, and for subjectingthe combination to the non-oxidizing atmosphere at the peak temperature,would be readily apparent to those of skill in the art based on thisdisclosure and, accordingly, are encompassed herein.

Step (i) can be conducted at a wide range of temperatures depending, forinstance, on the method used to combine the activator-support and thechromium (III) compound (e.g., dry blend, with a solvent, etc.). Whilenot being limited to any particular temperature range, step (i) oftencan be conducted at temperature in a range from about 0° C. to about100° C., from about 10° C. to about 100° C., from about 20° C. to about100° C., from about 0° C. to about 75° C., from about 10° C. to about75° C., from about 20° C. to about 75° C., from about 10° C. to about50° C., or from about 20° C. to about 50° C.

Likewise, step (ii) can be conducted at a wide range of peaktemperatures depending, for instance, on the type of mixture resultingfrom step (i). While not being limited thereto, the peak temperature canbe in a range from about 0° C. to about 600° C., from about 25° C. toabout 600° C., from about 10° C. to about 100° C., from about 20° C. toabout 100° C., from about 10° C. to about 500° C., from about 50° C. toabout 450° C., from about 100° C. to about 400° C., from about 100° C.to about 350° C., from about 150° C. to about 350° C., or from about200° C. to about 300° C. In these and other aspects, these peaktemperature ranges also are meant to encompass circumstances where step(ii) is conducted at a series of different temperatures (e.g., aninitial lower temperature, a higher peak temperature), instead of at asingle fixed temperature, falling within the respective ranges. Forinstance, step (ii) can start at a lower temperature (such as thetemperature used in step (i)), and subsequently, the temperature of step(ii) can be increased to the peak temperature, for example, a peaktemperature in a range from about 10° C. to about 600° C., or from about100° C. to about 550° C.

Step (ii) can be conducted over a wide range of time periods depending,for instance, on the peak temperature. While not being limited thereof,step (ii) often can be conducted for a time period in a range from about5 minutes to about 24-48 hours, from about 10 minutes to about 24 hours,from about 30 minutes to about 12 hours, from about 30 minutes to about9 hours, from about 1 hour to about 12 hours, from about 1 hour to about6 hours, or from about 2 hours to about 6 hours.

Importantly, the mixture of the activator-support and the chromium (III)compound, in step (ii), can be subjected to a non-oxidizing atmosphere(e.g., no oxygen). In one aspect, the non-oxidizing atmosphere is aninert atmosphere, while in another aspect, the non-oxidizing atmosphereis a reducing atmosphere. Hence, in some aspects, the non-oxidizingatmosphere can be an inert atmosphere comprising (or consistingessentially of, or consisting of) nitrogen, neon, argon, and the like,as well as combinations thereof. Additionally or alternatively, thenon-oxidizing atmosphere can comprise a vacuum (or other reducedpressure), for instance, to remove solvent to dry a wet mixture preparedin step (i). In other aspects, the non-oxidizing atmosphere can be areducing atmosphere comprising (or consisting essentially of, orconsisting of) H₂, CO, and the like, as well as combinations thereof.

In step (ii) of the process to produce a supported chromium catalyst,subjecting the mixture (e.g., exposing the mixture, treating themixture, etc.) to the non-oxidizing atmosphere at the peak temperatureallows the chromium (III) compound to be adsorbed and/or impregnatedand/or deposited onto the activator-support, thus resulting in thesupported chromium catalyst. During this process, the initial/startingchromium (III) compound may lose one ligand (or more ligands);therefore, the chromium (III) compound is meant to encompass such“derivatives” of the chromium (III) compound.

Polymerization Processes

Catalyst compositions of the present invention can be used to polymerizeolefins to form homopolymers, copolymers, terpolymers, and the like. Onesuch process for polymerizing olefins in the presence of a catalystcomposition of the present invention can comprise contacting thecatalyst composition with an olefin monomer and optionally an olefincomonomer (one or more) in a polymerization reactor system underpolymerization conditions to produce an olefin polymer, wherein thecatalyst composition can comprise a supported chromium catalystcomprising (a) a chromium (III) compound, or a derivative thereof, and(b) an activator-support comprising a solid oxide treated with anelectron-withdrawing anion; and a co-catalyst (one or more than one).Suitable chromium (III) compounds, activator-supports, and co-catalystsare discussed herein. Thus, a process for polymerizing olefins in thepresence of a catalyst composition can employ a catalyst compositioncomprising a supported chromium catalyst comprising (or consistingessentially of, or consisting of) chromium (III) acetylacetonate (orchromium (III) 2-ethylhexanoate, or chromium (III) naphthenate, orderivatives thereof) and sulfated alumina (or fluorided silica-alumina,or fluorided silica-coated alumina); and triethylaluminum (ortriisobutylaluminum).

The catalyst compositions of the present invention are intended for anyolefin polymerization method using various types of polymerizationreactor systems and reactors. The polymerization reactor system caninclude any polymerization reactor capable of polymerizing olefinmonomers and comonomers (one or more than one comonomer) to producehomopolymers, copolymers, terpolymers, and the like. The various typesof reactors include those that can be referred to as a batch reactor,slurry reactor, gas-phase reactor, solution reactor, high pressurereactor, tubular reactor, autoclave reactor, and the like, orcombinations thereof. Suitable polymerization conditions are used forthe various reactor types. Gas phase reactors can comprise fluidized bedreactors or staged horizontal reactors. Slurry reactors can comprisevertical or horizontal loops. High pressure reactors can compriseautoclave or tubular reactors. Reactor types can include batch orcontinuous processes. Continuous processes can use intermittent orcontinuous product discharge. Processes can also include partial or fulldirect recycle of unreacted monomer, unreacted comonomer, and/ordiluent.

Polymerization reactor systems of the present invention can comprise onetype of reactor in a system or multiple reactors of the same ordifferent type (e.g., a single reactor, dual reactor, more than tworeactors). Production of polymers in multiple reactors can includeseveral stages in at least two separate polymerization reactorsinterconnected by a transfer device making it possible to transfer thepolymers resulting from the first polymerization reactor into the secondreactor. The desired polymerization conditions in one of the reactorscan be different from the operating conditions of the other reactor(s).Alternatively, polymerization in multiple reactors can include themanual transfer of polymer from one reactor to subsequent reactors forcontinued polymerization. Multiple reactor systems can include anycombination including, but not limited to, multiple loop reactors,multiple gas phase reactors, a combination of loop and gas phasereactors, multiple high pressure reactors, or a combination of highpressure with loop and/or gas phase reactors. The multiple reactors canbe operated in series, in parallel, or both. Accordingly, the presentinvention encompasses polymerization reactor systems comprising a singlereactor, comprising two reactors, and comprising more than two reactors.The polymerization reactor system can comprise a slurry reactor, agas-phase reactor, a solution reactor, in certain aspects of thisinvention, as well as multi-reactor combinations thereof.

According to one aspect of the invention, the polymerization reactorsystem can comprise at least one loop slurry reactor comprising verticalor horizontal loops. Monomer, diluent, catalyst, and comonomer can becontinuously fed to a loop reactor where polymerization occurs.Generally, continuous processes can comprise the continuous introductionof monomer/comonomer, a catalyst, and a diluent into a polymerizationreactor and the continuous removal from this reactor of a suspensioncomprising polymer particles and the diluent. Reactor effluent can beflashed to remove the solid polymer from the liquids that comprise thediluent, monomer and/or comonomer. Various technologies can be used forthis separation step including, but not limited to, flashing that caninclude any combination of heat addition and pressure reduction,separation by cyclonic action in either a cyclone or hydrocyclone, orseparation by centrifugation.

A typical slurry polymerization process (also known as the particle formprocess) is disclosed, for example, in U.S. Pat. Nos. 3,248,179,4,501,885, 5,565,175, 5,575,979, 6,239,235, 6,262,191, and 6,833,415,each of which is incorporated herein by reference in its entirety.

Suitable diluents used in slurry polymerization include, but are notlimited to, the monomer being polymerized and hydrocarbons that areliquids under polymerization conditions. Examples of suitable diluentsinclude, but are not limited to, hydrocarbons such as propane,cyclohexane, isobutane, n-butane, n-pentane, isopentane, neopentane, andn-hexane. Some loop polymerization reactions can occur under bulkconditions where no diluent is used. An example is polymerization ofpropylene monomer as disclosed in U.S. Pat. No. 5,455,314, which isincorporated by reference herein in its entirety.

According to yet another aspect of this invention, the polymerizationreactor system can comprise at least one gas phase reactor. Such systemscan employ a continuous recycle stream containing one or more monomerscontinuously cycled through a fluidized bed in the presence of thecatalyst under polymerization conditions. A recycle stream can bewithdrawn from the fluidized bed and recycled back into the reactor.Simultaneously, polymer product can be withdrawn from the reactor andnew or fresh monomer can be added to replace the polymerized monomer.Such gas phase reactors can comprise a process for multi-step gas-phasepolymerization of olefins, in which olefins are polymerized in thegaseous phase in at least two independent gas-phase polymerization zoneswhile feeding a catalyst-containing polymer formed in a firstpolymerization zone to a second polymerization zone. One type of gasphase reactor is disclosed in U.S. Pat. Nos. 5,352,749, 4,588,790, and5,436,304, each of which is incorporated by reference in its entiretyherein.

According to still another aspect of the invention, a high pressurepolymerization reactor can comprise a tubular reactor or an autoclavereactor. Tubular reactors can have several zones where fresh monomer,initiators, or catalysts are added. Monomer can be entrained in an inertgaseous stream and introduced at one zone of the reactor. Initiators,catalysts, and/or catalyst components can be entrained in a gaseousstream and introduced at another zone of the reactor. The gas streamscan be intermixed for polymerization. Heat and pressure can be employedappropriately to obtain optimal polymerization reaction conditions.

According to yet another aspect of the invention, the polymerizationreactor system can comprise a solution polymerization reactor whereinthe monomer (and comonomer, if used) are contacted with the catalystcomposition by suitable stirring or other means. A carrier comprising aninert organic diluent or excess monomer can be employed. If desired, themonomer/comonomer can be brought in the vapor phase into contact withthe catalytic reaction product, in the presence or absence of liquidmaterial. The polymerization zone is maintained at temperatures andpressures that will result in the formation of a solution of the polymerin a reaction medium. Agitation can be employed to obtain bettertemperature control and to maintain uniform polymerization mixturesthroughout the polymerization zone. Adequate means are utilized fordissipating the exothermic heat of polymerization.

Polymerization reactor systems suitable for the present invention canfurther comprise any combination of at least one raw material feedsystem, at least one feed system for catalyst or catalyst components,and/or at least one polymer recovery system. Suitable reactor systemsfor the present invention can further comprise systems for feedstockpurification, catalyst storage and preparation, extrusion, reactorcooling, polymer recovery, fractionation, recycle, storage, loadout,laboratory analysis, and process control.

Polymerization conditions that are controlled for efficiency and toprovide desired polymer properties can include temperature, pressure,and the concentrations of various reactants. Polymerization temperaturecan affect catalyst productivity, polymer molecular weight, andmolecular weight distribution. A suitable polymerization temperature canbe any temperature below the de-polymerization temperature according tothe Gibbs Free energy equation. Typically, this includes from about 60°C. to about 280° C., for example, or from about 60° C. to about 120° C.,depending upon the type of polymerization reactor(s). In some reactorsystems, the polymerization temperature generally can fall within arange from about 70° C. to about 100° C., from about 80° C. to about110° C., or from about 75° C. to about 95° C. Various polymerizationconditions can be held substantially constant, for example, for theproduction of a particular grade of olefin polymer.

Suitable pressures will also vary according to the reactor andpolymerization type. The pressure for liquid phase polymerizations in aloop reactor is typically less than 1000 psig (6.9 MPa). Pressure forgas phase polymerization is usually at about 200 to 500 psig (1.4 MPa to3.4 MPa). High pressure polymerization in tubular or autoclave reactorsis generally run at about 20,000 to 75,000 psig (138 to 517 MPa).Polymerization reactors can also be operated in a supercritical regionoccurring at generally higher temperatures and pressures. Operationabove the critical point of a pressure/temperature diagram(supercritical phase) may offer advantages.

Aspects of this invention are directed to olefin polymerizationprocesses comprising contacting a catalyst composition with an olefinmonomer and, optionally, an olefin comonomer under polymerizationconditions to produce an olefin polymer. The olefin polymer (e.g.,ethylene homopolymer, ethylene copolymer, etc.) produced by the processcan have any of the polymer properties disclosed herein, for example, aMw in a range from about 400,000 to about 900,000 g/mol, and/or a ratioof Mw/Mn of greater than or equal to about 70, and/or a relaxation timeof less than or equal to about 100 sec, and/or less than or equal toabout 0.001 LCB per 1000 total carbon atoms, and/or a HLMI of less thanor equal to about 1 g/10 min.

Aspects of this invention also are directed to olefin polymerizationprocesses conducted in the absence of added hydrogen. An olefinpolymerization process of this invention can comprise contacting acatalyst composition with an olefin monomer and optionally an olefincomonomer in a polymerization reactor system under polymerizationconditions to produce an olefin polymer, wherein the catalystcomposition can comprise a supported chromium catalyst and aco-catalyst, and wherein the polymerization process is conducted in theabsence of added hydrogen (no hydrogen is added to the polymerizationreactor system). As one of ordinary skill in the art would recognize,hydrogen can be generated in-situ by certain catalyst compositions invarious olefin polymerization processes, and the amount generated canvary depending upon the specific catalyst components employed, the typeof polymerization process used, the polymerization reaction conditionsutilized, and so forth.

In other aspects, it may be desirable to conduct the polymerizationprocess in the presence of a certain amount of added hydrogen.Accordingly, an olefin polymerization process of this invention cancomprise contacting a catalyst composition with an olefin monomer andoptionally an olefin comonomer in a polymerization reactor system underpolymerization conditions to produce an olefin polymer, wherein thecatalyst composition comprises a supported chromium catalyst and aco-catalyst, and wherein the polymerization process is conducted in thepresence of added hydrogen (hydrogen is added to the polymerizationreactor system). For example, the ratio of hydrogen to the olefinmonomer in the polymerization process can be controlled, often by thefeed ratio of hydrogen to the olefin monomer entering the reactor. Theamount of hydrogen added (based on the amount of olefin monomer) to theprocess can be controlled at a molar percentage which generally fallswithin a range from about 0.05 to about 20 mole %, from about 0.1 toabout 15 mole %, from about 0.25 to about 10 mole %, or from about 0.5to about 10 mole %. In some aspects of this invention, the feed orreactant ratio of hydrogen to olefin monomer can be maintainedsubstantially constant during the polymerization run for a particularpolymer grade. That is, the hydrogen:olefin monomer ratio can beselected at a particular ratio, and maintained at the ratio to withinabout +/−25% during the polymerization run. Further, the addition ofcomonomer (or comonomers) can be, and generally is, substantiallyconstant throughout the polymerization run for a particular polymergrade.

However, in other aspects, it is contemplated that monomer, comonomer(or comonomers), and/or hydrogen can be periodically pulsed to thereactor, for instance, in a manner similar to that employed in U.S. Pat.No. 5,739,220 and U.S. Patent Publication No. 2004/0059070, thedisclosures of which are incorporated herein by reference in theirentirety.

Unexpectedly, the catalyst compositions and polymerization processes ofthe present invention can be much more sensitive to hydrogen thancomparable catalyst systems and processes employing Cr(VI). In oneaspect, for example, an increase in the melt index of the olefin polymerwith the addition of 1 mol % hydrogen (from 0 to 1 mol %, using thecatalyst compositions and polymerization processes described herein) canbe greater than the increase in the melt index of an olefin polymerobtained using a Cr(VI)/silica catalyst system, under the samepolymerization conditions. In another aspect, the melt index of anolefin polymer produced by the process in the presence of 0.5 mol %hydrogen (based on olefin monomer) can be greater than the melt index ofan olefin polymer obtained using a Cr(VI)/silica catalyst system, underthe same polymerization conditions. The Cr(VI) catalyst generally iscalcined in an oxidizing atmosphere at 600° C., and the polymerizationconditions can include slurry polymerization conditions, with a TIBAco-catalyst, using isobutane as the diluent, at a polymerizationtemperature of 100° C. and a reactor pressure of about 550 psig.

The concentration of the reactants entering the polymerization reactorsystem can be controlled to produce resins with certain physical andmechanical properties. The proposed end-use product that will be formedby the polymer resin and the method of forming that product ultimatelycan determine the desired polymer properties and attributes. Mechanicalproperties include tensile, flexural, impact, creep, stress relaxation,and hardness tests. Physical properties include density, molecularweight, molecular weight distribution, melting temperature, glasstransition temperature, temperature melt of crystallization, density,stereoregularity, crack growth, long chain branching, and rheologicalmeasurements.

This invention is also directed to, and encompasses, the polymersproduced by any of the polymerization processes disclosed herein.Articles of manufacture can be formed from, and/or can comprise, thepolymers produced in accordance with this invention.

Polymers and Articles

Olefin polymers encompassed herein can include any polymer produced fromany olefin monomer and optional comonomer(s) described herein. Forexample, the olefin polymer can comprise an ethylene homopolymer, anethylene copolymer (e.g., ethylene/α-olefin, ethylene/1-butene,ethylene/1-hexene, ethylene/1-octene, etc.), a propylene homopolymer, apropylene copolymer, an ethylene terpolymer, a propylene terpolymer, andthe like, including combinations thereof. In one aspect, the olefinpolymer can be an ethylene/1-butene copolymer, an ethylene/1-hexenecopolymer, or an ethylene/1-octene copolymer, while in another aspect,the olefin polymer can be an ethylene/1-hexene copolymer.

If the resultant polymer produced in accordance with the presentinvention is, for example, an ethylene polymer, its properties can becharacterized by various analytical techniques known and used in thepolyolefin industry. Articles of manufacture can be formed from, and/orcan comprise, the olefin polymers (e.g., ethylene polymers) of thisinvention, whose typical properties are provided below.

An illustrative and non-limiting example of an ethylene polymer of thepresent invention can have a Mw in a range from about 400,000 to about900,000 g/mol (or from about 300,000 to about 1,000,000 g/mol); a ratioof Mw/Mn of greater than or equal to about 70 (or greater than or equalto about 35, or greater than or equal to about 50, or greater than orequal to about 90); and a relaxation time of less than or equal to about100 sec (or less than or equal to about 70 sec, or less than or equal toabout 120 sec).

Another illustrative and non-limiting example of an ethylene polymer ofthe present invention can have a Mw in a range from about 400,000 toabout 900,000 g/mol (or from about 300,000 to about 1,000,000 g/mol); aratio of Mw/Mn of greater than or equal to about 70 (or greater than orequal to about 35, or greater than or equal to about 50, or greater thanor equal to about 90); and less than or equal to about 0.001 LCB per1000 total carbon atoms (or less than or equal to about 0.005 LCB per1000 total carbon atoms, or less than or equal to about 0.002 LCB per1000 total carbon atoms).

Yet another illustrative and non-limiting example of an ethylene polymerof the present invention can have a HLMI of less than or equal to about1 g/10 min (or less than or equal to about 5 g/10 min, or less than orequal to about 10 g/10 min); a ratio of Mw/Mn of greater than or equalto about 70 (or greater than or equal to about 35, or greater than orequal to about 50, or greater than or equal to about 90); and less thanor equal to about 0.001 LCB per 1000 total carbon atoms (or less than orequal to about 0.005 LCB per 1000 total carbon atoms, or less than orequal to about 0.002 LCB per 1000 total carbon atoms).

These illustrative and non-limiting examples of ethylene polymersconsistent with the present invention also can have any of the polymerproperties listed below and in any combination. Moreover, in particularaspects contemplated herein, these ethylene-based polymers can have aunimodal molecular weight distribution.

Polymers of ethylene (homopolymers, copolymers, terpolymers, etc.)produced in accordance with some aspects of this invention generally canhave a melt index (MI) from 0 to about 100 g/10 min. Melt indices in therange from 0 to about 50 g/10 min, from 0 to about 20 g/10 min, or from0 to about 10 g/10 min, are contemplated in other aspects of thisinvention. For example, a polymer of the present invention can have amelt index in a range from 0 to about 5, from 0 to about 3, from 0 toabout 1, from 0 to about 0.5, from 0 to about 0.25, or from 0 to about0.1 g/10 min.

Ethylene polymers produced in accordance with this invention can have ahigh load melt index (HLMI) of less than or equal to about 1000, lessthan or equal to about 500, less than or equal to about 100, less thanor equal to about 10, less than or equal to about 5, or less than orequal to about 1 g/10 min. Suitable ranges for the HLMI can include, butare not limited to, from 0 to about 100, from 0 to about 25, from 0 toabout 10, from 0 to about 5, from 0 to about 3, from 0 to about 2, from0 to about 1.5, from 0 to about 1, from 0 to about 0.75, or from 0 toabout 0.5 g/10 min.

The densities of ethylene-based polymers produced using the catalystsystems and processes disclosed herein often are greater than or equalto about 0.89 g/cm³. In one aspect of this invention, the density of theethylene polymer can be in a range from about 0.90 to about 0.97 g/cm³.Yet, in another aspect, the density can be in a range from about 0.91 toabout 0.96 g/cm³, such as, for example, from about 0.92 to about 0.96g/cm³, from about 0.93 to about 0.955 g/cm³, or from about 0.94 to about0.95 g/cm³.

In an aspect, ethylene polymers described herein can have a ratio ofMw/Mn, or the polydispersity index, of greater than or equal to about25, greater than or equal to about 35, greater than or equal to about50, greater than equal to about 70, greater than or equal to about 90,or greater than or equal to about 100. Often, the Mw/Mn can range up toabout 150-200, therefore, non-limiting ranges for Mw/Mn include fromabout 25 to about 200, from about 35 to about 200, from about 50 toabout 200, from about 70 to about 200, from about 90 to about 200, fromabout 25 to about 150, from about 35 to about 150, from about 50 toabout 150, from about 70 to about 150, or from about 90 to about 150.

In an aspect, ethylene polymers described herein can have a ratio ofMz/Mw in a range from about 1.5 to about 10, from about 2 to about 10,from about 2 to about 8, from about 2.5 to about 8, from about 3 toabout 10, or from about 3 to about 8. In another aspect, ethylenepolymers described herein can have a Mz/Mw in a range from about 2 toabout 7, from about 2 to about 6, from about 2 to about 5, or from about2 to about 4.

In an aspect, ethylene polymers described herein can have aweight-average molecular weight (Mw) in a range from about 200,000 toabout 5,000,000, from about 200,000 to about 2,000,000, from about300,000 to about 1,500,000, from about 300,000 to about 1,000,000, fromabout 400,000 to about 2,000,000, or from about 400,000 to about1,000,000 g/mol. In another aspect, ethylene polymers described hereincan have a Mw in a range from about 400,000 to about 900,000, from about450,000 to about 1,000,000, or from about 500,000 to about 900,000g/mol.

In an aspect, ethylene polymers described herein can have anumber-average molecular weight (Mn) in a range from about 2,000 toabout 60,000, from about 2,000 to about 50,000, from about 2,000 toabout 25,000, from about 2,000 to about 20,000, from about 3,000 toabout 50,000, or from about 3,000 to about 25,000 g/mol. In anotheraspect, ethylene polymers described herein can have a Mn in a range fromabout 3,000 to about 20,000, from about 3,000 to about 19,000, fromabout 4,000 to about 45,000, from about 4,000 to about 25,000, or fromabout 4,000 to about 15,000 g/mol.

In an aspect, ethylene polymers described herein can have a z-averagemolecular weight (Mz) in a range from about 500,000 to about 6,000,000,from about 1,000,000 to about 6,000,000, from about 1,500,000 to about6,000,000, from about 1,000,000 to about 5,000,000, from about 1,000,000to about 4,500,000, or from about 1,500,000 to about 4,000,000 g/mol. Inanother aspect, ethylene polymers described herein can have a Mz in arange from about 2,000,000 to about 5,000,000, from about 2,000,000 toabout 4,500,000, from about 2,000,000 to about 4,000,000, or from about2,000,000 to about 3,500,000 g/mol.

Generally, polymers produced in aspects of the present invention havelow levels of long chain branching, with typically less than or equal toabout 0.01 long chain branches (LCB) per 1000 total carbon atoms, andmore often, less than or equal to about 0.008 LCB per 1000 total carbonatoms, or less than or equal to about 0.005 LCB per 1000 total carbonatoms, as determined by the Janzen-Colby method. In some aspects, thenumber of LCB per 1000 total carbon atoms can be less than or equal toabout 0.003, or less than or equal to about 0.002 LCB per 1000 totalcarbon atoms. Further, the olefin polymer can have less than or equal toabout 0.001 LCB per 1000 total carbon atoms in particular aspects ofthis invention. Surprisingly, olefin polymers (e.g., ethylene polymers)produced using the catalyst systems and polymerization processesdescribed herein can the lowest levels of LCB recorded for achromium-based catalyst system. Long chain branches (LCB) per 1000 totalcarbon atoms can be determined using the Janzen-Colby method asdescribed in J. Mol. Struct., 485/486, 569-584 (1999); see also U.S.Pat. No. 8,114,946; J. Phys. Chem. 1980, 84, 649; and Y. Yu, D. C.Rohlfing, G. R Hawley, and P. J. DesLauriers, Polymer Preprints, 44,49-50 (2003). These references are incorporated herein by reference intheir entirety.

Ethylene copolymers, for example, produced using the polymerizationprocesses and catalyst systems described hereinabove can, in someaspects, have a conventional comonomer distribution; generally, thelower molecular weight components of the polymer have higher comonomerincorporation than the higher molecular weight components. Typically,there is decreasing comonomer incorporation with increasing molecularweight. In one aspect, the number of short chain branches (SCB) per 1000total carbon atoms of the polymer can be greater at Mn than at Mz. Inanother aspect, the number of SCB per 1000 total carbon atoms of thepolymer can be greater at Mn than at Mw.

In an aspect, ethylene polymers described herein can have a relaxationtime of less than or equal to about 500 sec, less than or equal to about200 sec, or less than or equal to about 150 sec (determined by theCarreau-Yasuda method, as described herein). In another aspect, therelaxation time can be less than or equal to about 120 sec, or less thanor equal to about 100 sec. Yet, in another aspect, the ethylene polymercan have a relaxation time of less than or equal to about 85 sec, lessthan or equal to about 75 sec, less than or equal to about 70 sec, lessthan or equal to about 50 sec, or less than or equal to about 40 sec.Often, the relaxation time for polymers described herein can be greaterthan or equal to about 20 sec. Moreover, in some aspects, the relaxationtimes for polymers disclosed herein can be shorter than for comparable(same Mw) polymers produced using a chromium (VI) catalyst system.

Polymers of ethylene, whether homopolymers, copolymers, and so forth,can be formed into various articles of manufacture. Articles which cancomprise polymers of this invention include, but are not limited to, anagricultural film, an automobile part, a bottle, a drum, a fiber orfabric, a food packaging film or container, a food service article, afuel tank, a geomembrane, a household container, a liner, a moldedproduct, a medical device or material, a pipe, a sheet or tape, a toy,and the like. Various processes can be employed to form these articles.Non-limiting examples of these processes include injection molding, blowmolding, rotational molding, film extrusion, sheet extrusion, profileextrusion, thermoforming, and the like. Additionally, additives andmodifiers are often added to these polymers in order to providebeneficial polymer processing or end-use product attributes. Suchprocesses and materials are described in Modern Plastics Encyclopedia,Mid-November 1995 Issue, Vol. 72, No. 12; and Film ExtrusionManual—Process, Materials, Properties, TAPPI Press, 1992; thedisclosures of which are incorporated herein by reference in theirentirety.

Applicants also contemplate a method for forming or preparing an articleof manufacture comprising a polymer produced by any of thepolymerization processes disclosed herein. For instance, a method cancomprise (i) contacting a catalyst composition with an olefin monomerand an optional olefin comonomer under polymerization conditions in apolymerization reactor system to produce an olefin polymer, wherein thecatalyst composition can comprise a supported chromium (III) catalystand a co-catalyst; and (ii) forming an article of manufacture comprisingthe olefin polymer (e.g., having any of the polymer properties disclosedherein). The forming step can comprise blending, melt processing,extruding, molding, or thermoforming, and the like, includingcombinations thereof.

EXAMPLES

The invention is further illustrated by the following examples, whichare not to be construed in any way as imposing limitations to the scopeof this invention. Various other aspects, embodiments, modifications,and equivalents thereof which, after reading the description herein, maysuggest themselves to one of ordinary skill in the art without departingfrom the spirit of the present invention or the scope of the appendedclaims.

Melt index (MI, g/10 min) was determined in accordance with ASTM D1238at 190° C. with a 2,160 gram weight. High load melt index (HLMI, g/10min) was determined in accordance with ASTM D1238 at 190° C. with a21,600 gram weight.

Polymer density was determined in grams per cubic centimeter (g/cm³) ona compression molded sample, cooled at about 15° C. per hour, andconditioned for about 40 hours at room temperature in accordance withASTM D1505 and ASTM D4703.

Molecular weights and molecular weight distributions were obtained usinga PL-GPC 220 (Polymer Labs, an Agilent Company) system equipped with aIR4 detector (Polymer Char, Spain) and three Styragel HMW-6E GPC columns(Waters, Mass.) running at 145° C. The flow rate of the mobile phase1,2,4-trichlorobenzene (TCB) containing 0.5 g/L2,6-di-t-butyl-4-methylphenol (BHT) was set at 1 mL/min, and polymersolution concentrations were in the range of 1.0-1.5 mg/mL, depending onthe molecular weight. Sample preparation was conducted at 150° C. fornominally 4 hr with occasional and gentle agitation, before thesolutions were transferred to sample vials for injection. An injectionvolume of about 200 μL was used. The integral calibration method wasused to deduce molecular weights and molecular weight distributionsusing a Chevron Phillips Chemicals Company's HDPE polyethylene resin,MARLEX® BHB5003, as the broad standard. The integral table of the broadstandard was pre-determined in a separate experiment with SEC-MALS. Mnis the number-average molecular weight, Mw is the weight-averagemolecular weight, Mz is the z-average molecular weight, and Mp is thepeak molecular weight.

Melt rheological characterizations were performed as follows.Small-strain (10%) oscillatory shear measurements were performed on aRheometrics Scientific, Inc. ARES rheometer using parallel-plategeometry. All rheological tests were performed at 190° C. The complexviscosity |η*| versus frequency (ω) data were then curve fitted usingthe modified three parameter Carreau-Yasuda (CY) empirical model toobtain the zero shear viscosity—η₀, characteristic viscous relaxationtime—τ_(η), and the breadth parameter—α. The simplified Carreau-Yasuda(CY) empirical model is as follows.

${{{\eta^{*}(\omega)}} = \frac{\eta_{0}}{\left\lbrack {1 + \left( {\tau_{\eta}\omega} \right)^{a}} \right\rbrack^{{({1 - n})}/a}}},$wherein:

-   -   |η*(ω)|=magnitude of complex shear viscosity;    -   η₀=zero shear viscosity;    -   τ_(n)=viscous relaxation time;    -   α=“breadth” parameter (CY-a parameter);    -   n=fixes the final power law slope, fixed at 2/11; and    -   ω=angular frequency of oscillatory shearing deformation.

Details of the significance and interpretation of the CY model andderived parameters may be found in: C. A. Hieber and H. H. Chiang,Rheol. Acta, 28, 321 (1989); C. A. Hieber and H. H. Chiang, Polym. Eng.Sci., 32, 931 (1992); and R. B. Bird, R. C. Armstrong and O. Hasseger,Dynamics of Polymeric Liquids, Volume 1, Fluid Mechanics, 2nd Edition,John Wiley & Sons (1987); each of which is incorporated herein byreference in its entirety.

The long chain branches (LCB) per 1000 total carbon atoms werecalculated using the method of Janzen and Colby (J. Mol. Struct.,485/486, 569-584 (1999)), from values of zero shear viscosity, η_(o)(determined from the Carreau-Yasuda model, described hereinabove), andmeasured values of Mw obtained using a Dawn EOS multiangle lightscattering detector (Wyatt). See also U.S. Pat. No. 8,114,946; J. Phys.Chem. 1980, 84, 649; and Y. Yu, D. C. Rohlfing, G. R Hawley, and P. J.DesLauriers, Polymer Preprints, 44, 49-50 (2003). These references areincorporated herein by reference in their entirety.

Short chain branch content and short chain branching distribution (SCBD)across the molecular weight distribution were determined via anIRS-detected GPC system (IR5-GPC), wherein the GPC system was a PL220GPC/SEC system (Polymer Labs, an Agilent company) equipped with threeStyragel HMW-6E columns (Waters, Mass.) for polymer separation. Athermoelectric-cooled IRS MCT detector (IRS) (Polymer Char, Spain) wasconnected to the GPC columns via a hot-transfer line. Chromatographicdata were obtained from two output ports of the IRS detector. First, theanalog signal goes from the analog output port to a digitizer beforeconnecting to Computer “A” for molecular weight determinations via theCirrus software (Polymer Labs, now an Agilent Company) and the integralcalibration method using a broad MWD HDPE Marlex™ BHB5003 resin (ChevronPhillips Chemical) as the broad molecular weight standard. The digitalsignals, on the other hand, go via a USB cable directly to Computer “B”where they are collected by a LabView data collection software providedby Polymer Char. Chromatographic conditions were set as follows: columnoven temperature of 145° C.; flowrate of 1 mL/min; injection volume of0.4 mL; and polymer concentration of about 2 mg/mL, depending on samplemolecular weight. The temperatures for both the hot-transfer line andIRS detector sample cell were set at 150° C., while the temperature ofthe electronics of the IRS detector was set at 60° C. Short chainbranching content was determined via an in-house method using theintensity ratio of CH₃ (I_(CH3)) to CH₂ (I_(CH2)) coupled with acalibration curve. The calibration curve was a plot of SCB content(x_(SCB)) as a function of the intensity ratio of I_(CH3)/I_(CH2). Toobtain a calibration curve, a group of polyethylene resins (no less than5) of SCB level ranging from zero to ca. 32 SCB/1,000 total carbons (SCBStandards) were used. All these SCB Standards have known SCB levels andflat SCBD profiles pre-determined separately by NMR and thesolvent-gradient fractionation coupled with NMR (SGF-NMR) methods. UsingSCB calibration curves thus established, profiles of short chainbranching distribution across the molecular weight distribution wereobtained for resins fractionated by the IR5-GPC system under exactly thesame chromatographic conditions as for these SCB standards. Arelationship between the intensity ratio and the elution volume wasconverted into SCB distribution as a function of MWD using apredetermined SCB calibration curve (i.e., intensity ratio ofI_(CH3)/I_(CH2) vs. SCB content) and MW calibration curve (i.e.,molecular weight vs. elution time) to convert the intensity ratio ofI_(CH3)/I_(CH2) and the elution time into SCB content and the molecularweight, respectively.

Silica, grade EP10 from Philadelphia Quartz, was calcined in dry air at600° C. for three hours. Alumina, grade A from W.R. Grace Co., wascalcined in dry air at 600° C. for three hours. Aluminophosphate wasprepared by co-precipitation as described in U.S. Pat. No. 4,364,855, tocontain a P/Al molar ratio of 0.9, 0.6, or 0.2, as indicated, followedby calcining in dry air for three hours at 600° C.

Fluorided silica-coated aluminas were prepared as follows. Bohemite wasobtained from W.R. Grace & Company under the designation “Alumina A” andhaving a surface area of about 300 m²/g, a pore volume of about 1.3mL/g, and an average particle size of about 100 microns. The alumina wasfirst calcined in dry air at about 600° C. for approximately 6 hours,cooled to ambient temperature, and then contacted withtetraethylorthosilicate in isopropanol to equal 25 wt. % SiO₂. Afterdrying, the silica-coated alumina was calcined at 600° C. for 3 hours.Fluorided silica-coated alumina (7 wt. % F) was prepared by impregnatingthe calcined silica-coated alumina with an ammonium bifluoride solutionin methanol, drying, and then calcining for 3 hours at 600° C. (unlessotherwise noted) in dry air. Afterward, the fluorided silica-coatedalumina was collected and stored under dry nitrogen, and was usedwithout exposure to the atmosphere.

Silica-coated alumina samples that were treated with both chloride andfluoride were made as follows. First, Alumina A was treated with silicontetraethoxide as described above. Then, this material was heated in dryair to 600° C., where it was treated with carbon tetrachloride vapor(0.2 g CCl₄/g alumina), followed by a treatment with tetrafluoroethanevapor to result in a F loading of 7 wt. % F.

Hexavalent chromium catalysts (Examples 35-37) were prepared byimpregnating the support (silica, alumina, or silica-coated alumina)with an aqueous solution of chromium trioxide to equal a final chromiumloading of 1 wt. % Cr. These catalysts were then calcined at thespecified temperature (600 or 700° C.) in dry air (an oxidizingatmosphere) in order to maintain the chromium in the hexavalent state.

Sulfated alumina activator-supports were prepared as follows. Bohemitewas obtained from W.R. Grace & Company under the designation “Alumina A”and having a surface area of about 300 m²/g and a pore volume of about1.3 mL/g. This material was obtained as a powder having an averageparticle size of about 100 microns. This material was impregnated toincipient wetness with an aqueous solution of ammonium sulfate to equalabout 1.5 mmol/g or 3.6 mmol/g sulfate. This mixture was then placed ina flat pan and allowed to dry under vacuum at approximately 110° C. forabout 16 hours. To calcine the resultant powdered mixture, the materialwas fluidized in a stream of dry air at about 400° C. or 600° C., asnoted, for 3 hours. Afterward, the sulfated alumina was collected andstored under dry nitrogen, and was used without exposure to theatmosphere.

Fluorided silica-alumina was prepared from a support containing 13 wt. %alumina, a surface area of 450 m²/g, and a pore volume of 1.3 mL/g Afterimpregnation with an aqueous solution of ammonium bifluoride to contain7 wt. % fluoride, the material was dried and then calcined at 450° C.for three hours.

Chlorided zinc-aluminate was prepared by impregnating the same aluminadescribed above with 1.5 mmol/g of zinc acetate. After drying, it wascalcined at 600° C. in nitrogen. During the calcination of 10 g of thissupport, 1 mL of carbon tetrachloride was added and vaporized into thenitrogen. Then, the support was collected in a sealed nitrogen-blanketedbottle.

Fluorided silica-coated Ti-alumina was prepared from the same alumina asdescribed above. The calcined (600° C.) Alumina A was first slurried indry isopropanol, to which was added enough titanium tetraisopropoxide toyield 8 wt. % TiO₂ upon calcination. Then, silicon tetraethoxide wasadded to yield 25 wt. % SiO₂ upon calcination. The solvent wasevaporated, and the dried support was calcined at 500° C. in air for 3hours. During the calcination, perfluorohexane was injected into the airsource to equal 7 wt. % F.

The support or activator-support materials in Table I were calcined atthe respective temperature listed in Table I for 3 hours, as describedabove. Then, at room temperature, each support or activator-supportmaterial was impregnated with a toluene solution of chromium (III)acetylacetonate (Cr(AcAc)₃) to equal 2 wt. % Cr, followed by heating at110° C. in N₂ for 1 hour. The resultant supported chromium catalyst wasused in polymerization experiments conducted in a 2-L stainless steelreactor. Isobutane (1.2 L) was used in all runs. Approximately 0.05-0.10g of the supported chromium catalyst and 1 mmol of triisobutylaluminum(TIBA) were added through a charge port while slowly venting isobutanevapor. The charge port was closed and the isobutane was added. Thecontents of the reactor were stirred and heated to the desired runtemperature of about 100° C., and ethylene was then introduced into thereactor. Ethylene was fed on demand to maintain a concentration of 1.7mol/liter (based on isobutane volume), which was a reactor pressure ofabout 550 psig, for the 60 minute length of the polymerization run. Thereactor was maintained at the desired run temperature throughout the runby an automated heating-cooling system. Table I summarizes certainpolymer properties and catalyst activities relating to thepolymerization experiments of Examples 1-9. Unexpectedly, the catalystactivities for Examples 5-7, which utilized certain fluorided orsulfated solid oxide activator-supports, were an order of magnitudehigher than the catalyst activities using conventional solid oxidematerials (catalyst activity in grams of polyethylene per gram ofsupported chromium catalyst per hour). Additionally, as shown in TableI, the polymers produced had surprisingly high molecular weights andbroad molecular weight distributions (e.g., HLMI less than 10, Mw from400,000 to 800,000 g/mol, Mz around 3,000,000 to 3,500,000 g/mol, andMw/Mn from about 65 to about 100).

The support or activator-support materials in Table II were calcined atthe respective temperature listed in Table II for 3 hours, as indicatedabove. Then, at room temperature, each support or activator-supportmaterial was dry mixed with Cr(AcAc)₃ to equal 2 wt. % Cr (unless notedotherwise), followed by heating at 120-250° C. in N₂ for 1 hour. Theresultant supported chromium catalyst was used in polymerizationexperiments as described above for Examples 1-9. Table II summarizescertain polymer properties and catalyst activities relating to thepolymerization experiments of Examples 10-37. Similar to Table I, andunexpectedly, the catalyst activities for Examples 22-34, which utilizedcertain activator-supports, were generally higher than the catalystactivities using conventional solid oxide materials (catalyst activityin grams of polyethylene per gram of supported chromium catalyst perhour). In particular, the activities for Examples 22-27 and 33-34 rangedfrom about 2500 to about 7000 g/g/hr. Analogously to Table I, thepolymers in Table II also had surprisingly high molecular weights andbroad molecular weight distributions.

Relaxation time data in Table I and Table II demonstrate theunexpectedly low relaxation time for the polymers produced using theCr(III)/activator-support based catalyst systems. The relaxation timesfor the polymers of Examples 5-9 generally were in the 50-80 secondrange, and the relaxation times for the polymers of Examples 22-28 and31-34 generally were in the 30-85 second range. In contrast, thepolymers of Examples 35-37, produced using chromium (VI) catalystsystems, had relaxation times in the 135-300 second range.

Regarding FIG. 1, fluorided silica-coated alumina, described above inTable I and Table II, was dry mixed with Cr(AcAc)₃ as described above (2wt. % Cr), and then calcined at various temperatures between 150° C. and600° C. in either nitrogen, carbon monoxide, or hydrogen. FIG. 1illustrates the catalyst activity obtained from these catalysts inpolymerization experiments as described above for Examples 1-9 (100° C.and 550 psig). Generally, peak temperatures in the 200-400° C. rangeresulted in the highest catalyst activity. Catalyst activities listedare in grams of polyethylene per gram of supported chromium catalyst perhour.

FIG. 2 illustrates a typical molecular weight distribution (amount ofpolymer versus the logarithm of molecular weight) of a polymer producedusing the catalyst systems described herein (labeled Cr(+3), Example 5with fluorided silica-coated alumina). It is compared to three standardcommercially-available chromium-based polymers. The polymer with thenarrow peak (Polymer A) had a nominal 0.35 melt index and 0.955 density,and was made with Cr(VI)/silica catalyst calcined at 780° C. The othertwo curves show Cr(VI) catalysts which produce a very broad MWD. The MWDcurve labeled Polymer C was for a polymer having a nominal 4 HLMI and0.949 density, which was made under similar conditions (100° C., 550psig) using a Cr(VI)/aluminophosphate catalyst according to U.S. Pat.No. 6,525,148. The MWD curve labeled Polymer B was for a nominal 10 HLMIand 0.947 density polymer, which was made with Cr(VI)/silica-titania.Thus, FIG. 2 demonstrates the high molecular weight and broaddistribution polymers produced in accordance with this invention.

FIG. 3 illustrates that the high molecular weight and broad distributionpolymers described herein can be produced using differentactivator-supports, and the support can influence the MWD. Threeactivator-supports were used: fluorided silica-coated alumina, fluoridedsilica-alumina, and sulfated alumina. In each case, the support wasimpregnated with a toluene solution of Cr(AcAc)₃ as described above, andheated in nitrogen at 250° C. Polymerization conditions were asdescribed above for Examples 1-9 (100° C., 550 psig, 1 mmol TIBA, etc.).

FIG. 4 illustrates that the high molecular weight and broad distributionpolymers described herein can be produced using supported catalystsexposed to different non-oxidizing atmospheres: N₂ and CO. Thesecatalysts were prepared by dry mixing Cr(AcAc)₃ with fluoridedsilica-coated alumina to equal 2 wt. % Cr, then heating the catalyst ineither N₂ or CO at 450° C. for 1 hour. Polymerization conditions were asdescribed above for Examples 1-9.

FIG. 5 illustrates the impact of the peak treatment temperature used toprepare the supported catalyst on the weight-average molecular weight(Mw). The catalyst system of Example 25 was treated in either a N₂ or COatmosphere at various temperatures, and polymerization conditions wereas described above for Examples 1-9. Surprisingly, the Mw increased withincreasing temperature, which is opposite to the behavior of Cr(VI)catalysts (see McDaniel, Advances in Catalysis, 2010, Chapter 3,incorporated herein by reference). Also unexpectedly, the nitrogentreatment resulted in higher molecular weights than carbon monoxidetreatment, at each temperature tested.

FIG. 6 illustrates the impact of the peak treatment temperature in N₂ onthe molecular weight distribution. The catalyst system of Example 25 wastreated in a N₂ atmosphere at various peak sublimation temperatures, andpolymerization conditions were as described above for Examples 1-9.Interestingly, the MWD was largely unaffected by the treatmenttemperature, although there appeared to be a slight change in themolecular weight with increasing temperature.

FIG. 7 presents an “Arnett plot,” wherein the log of the zero-shearviscosity is plotted against the log of the weight-average molecularweight. When each point is compared to the Janzen-Colby grid lines, theaverage number of long chain branches (LCB) in the polymer can bedetermined. FIG. 7 shows the unexpectedly low levels of LCB in thepolymers produced using fluorided silica-coated alumina (M), fluoridedsilica-alumina (F), sulfated alumina (S), and chlorided zinc-aluminate(CO, as compared to the LCB content of commercially available Cr(VI)based polymers.

FIG. 8 is another Arnett plot that illustrates how the LCB content isinfluenced by the treatment temperature and the Cr loading on thecatalyst. The catalyst system of Example 25 was modified with differentchromium loadings and treated in a N₂ atmosphere at peak sublimationtemperatures of either 110° C. or 250° C., and polymerization conditionswere as described above for Examples 1-9. Unexpectedly, the lowertreatment temperature resulted in slightly lower LCB content, and as Crloading decreased, the LCB content generally increased. This behavior isopposite to that of Cr(VI) catalysts (see McDaniel, Advances inCatalysis, 2010, Chapter 3). Again, polymers produced using chromium(III) compounds had unexpectedly low levels of LCB as compared tostandard Cr(VI) catalyst systems.

FIG. 9 illustrates the surprising impact of hydrogen addition duringpolymerization on the molecular weight distributions of the polymersdescribed herein, which were produced using the catalyst system ofExample 25 under polymerization conditions as described above forExamples 1-9, with the exception of the hydrogen addition. Additionalresults using the same chromium (III) catalyst system are tabulated inTable III and compared to polymers made with a standard Cr(VI)/silicacatalyst. Both FIG. 9 and Table III demonstrate the unexpected hydrogensensitivity of chromium (III) based catalyst systems. In Table III,there is a dramatic increase in melt index as hydrogen is added to thereactor. This is an unexpected and very important characteristic,because it allows virtually any target melt index to be produced, whichis not always possible with Cr(VI) catalyst systems. In FIG. 9, theaddition of hydrogen has a dramatic change on the molecular weightdistribution. In contrast, Cr(VI) catalyst systems have very littlesensitivity to hydrogen, as a regulator of molecular weight. TheCr(VI)/silica catalyst in Table III was activated at 800° C., andpolymerization conditions were as described above for Examples 1-9,except for the addition of hydrogen. The melt index for polymersproduced using Cr(VI) were largely unaffected by hydrogen addition. Insum, the melt index and molecular weight distribution for polymersproduced using Cr(III) catalyst systems were significantly, andunexpectedly, affected by hydrogen addition, which can be a very usefulfeature for commercial polyethylene production.

Co-catalysts other than TIBA can be used in accordance with aspects ofthis invention. FIG. 10 illustrates the impact of the co-catalyst typeon the molecular weight distribution of the polymers produced using atrimethylaluminum, triethylaluminum, or triisobutylaluminum co-catalyst.The catalyst system of Example 25 was used, as were the polymerizationconditions described above for Examples 1-9, with the exception of theco-catalyst type (1 mmol used). FIG. 10 demonstrates that the choice ofco-catalyst does not significantly impact the MWD.

FIG. 11 shows that, unexpectedly, the catalysts of this invention cantolerate high levels of aluminum alkyl co-catalysts. Whereas Cr(VI)catalyst systems can lose most of their activity when treated withgreater than 10 ppm (0.05 mmol/L) of triethylaluminum (see McDaniel,Advances in Catalysis, 2010, Chapter 3), the catalysts of this inventioncan tolerate concentrations of co-catalyst of up to 2 mmol/L and above.Hence, these catalysts can be used in combination with other catalysttypes that may require high concentrations of co-catalysts, e.g.,metallocenes, Ziegler catalysts, etc. The catalyst system of Example 25was used, as were the polymerization conditions described above forExamples 1-9, with the exception of the amount of TIBA co-catalyst used(in mmol per liter of isobutane).

FIG. 12 shows the molecular weight distributions of some of the polymerswhose catalyst activity is presented in FIG. 11. That is, FIG. 12 showsthe effect of the co-catalyst loading on the molecular weightdistribution of polymers produced using the catalyst system of Example25 and the polymerization conditions as described above for Examples1-9, with the exception being the amount of co-catalyst per liter ofisobutane. Generally, the amount of the co-catalyst did notsignificantly impact the MWD.

Chromium (III) compounds other than Cr(AcAc)₃ can be used in accordancewith aspects of this invention, e.g., other suitable Cr(III) carboxylatecompounds can be used. In a manner similar to Example 25, catalystsystems were produced with chromium (III) napthenate and chromium (III)2-ethylhexanoate, and polymerization experiments were conducted asdescribed above for Examples 1-9. FIG. 13 illustrates the MWD of thepolymers obtained using these chromium (III) compounds; the selection ofthe Cr(III) compound did not significantly impact the MWD. Accordingly,the unexpected results described herein appear generally applicable toother chromium (III) compounds, e.g., carboxylates, dionates, etc.

The polymers produced in the examples above were ethylene homopolymers,meaning that no comonomer (1-hexene, 1-butene, 1-octene, etc.) was addedto the reactor during polymerization. In spite of this, the polymerdensity was depressed somewhat, indicating that olefins may have beengenerated and incorporated into the polymers as branches. Nonetheless,the catalysts of this invention also can be used to produce copolymersof any desired density. In an experiment similar to that of Example 25,the same activator-support (fluorided silica-coated alumina) was drymixed with Cr(AcAc)₃ to equal 2 wt. % Cr, then heated in nitrogen at250° C. for 1 hour. This supported chromium catalyst was then testedunder slightly different reaction conditions: a 95° C. reactiontemperature, with 30 mL of 1-hexene added to the reactor. The resultingcopolymer had a density of 0.936 g/mL, instead of the nominal 0.95density for the homopolymer. The copolymer was analyzed as describedherein to determine where the branches were incorporated within the MWD.FIG. 14 illustrates that the SCB's were incorporated more in the lowermolecular weight portions of the copolymer, which is typical ofcopolymers produced using commercial Cr(VI) catalysts. Thus, thecopolymers of this invention can have a conventional comonomerdistribution, similar to that of commercial Cr(VI) based copolymers.

Because the chromium (III) catalysts of this invention can tolerate highlevels of co-catalyst, unlike typical Cr(VI) catalysts, the chromium(III) catalysts can be used with other catalysts to produce a dualcomponent MWD, often a bimodal MWD. In a series of experiments, astandard Cr(III) catalyst of this invention (i.e., fluoridedsilica-coated alumina dry mixed with Cr(AcAc)₃, and then heated innitrogen at 250° C. for 1 hour) was used in combination with ametallocene compound. The metallocene compound can be activated by thesame activator-support (in the absence of MAO or other activators). Themetallocene compound used is shown below:

The supported catalyst of this invention was charged to the reactor with1 mmol TIBA co-catalyst, and a small amount of a solution containing themetallocene compound. The activator-support activated both metals, theCr on the support and the Zr in the metallocene, to produce a dualcomponent MWD. The amount of the metallocene added to the reactor wasvaried to produce a range of Zr:Cr molar ratios. FIG. 15 demonstratesthat a range of MWD's can be produced depending upon the Zr:Cr molarratio added to the reactor, thus producing a broad range of differenttypes of polymers. This dual catalyst system and dual component polymerare not possible using standard Cr(VI) catalyst systems.

TABLE I Example 1-9 Calc. Activity HLMI Density M_(N) M_(W) M_(Z)Relaxation Example Support Temp. gPE/g/h (g/10 min) g/mL kg/mol kg/molkg/mol Mw/Mn Time (sec) 1 Silica (EP10) 600° C. 56 1.5 0.9505 8.83 6373139 72.1 52 2 Alumina (Grace A) 600° C. 103 1.2 0.9512 9.52 653 320568.6 28 3 Aluminophosphate (P/Al 0.9) 600° C. 150 9.4 0.9612 5.56 4683086 84.2 98 4 Si-Coated Alumina 600° C. 141 0.5 0.9515 9.55 801 342783.9 58 5 F—Si-Coated Alumina 600° C. 2167 0.4 0.9472 10.15 770 311675.9 70 6 F-Silica-Alumina 500° C. 1270 5.3 0.9531 5.13 494 3229 96.3 547 SO₄/Alumina, 1.5 mmol SO4/g 600° C. 2083 0.9 0.9506 7.88 734 3449 93.181 8 SO₄/Alumina, 3.6 mmol SO4/g 400° C. 276 1.5 0.9538 9.26 739 288179.8 73 9 Cl—Zn/Alumina 600° C. 43 1.1 0.9565 9.54 796 3177 83.4 70

TABLE II Examples 10-37 Relaxation Calc. CrAcAc Activity HLMI DensityM_(N) M_(W) M_(Z) Time Example Support Temp. N2 at gPE/g/h (g/10 min)g/mL kg/mol kg/mol kg/mol Mw/Mn (sec) 10 Silica 600° C. 250° C. 120 NANA NA NA NA NA 102 11 Alumina 600° C. 250° C. 0 NA NA NA NA NA NA NA 12Alumina 600° C. 250° C. 55 0.064 0.9523 6.7 1136 3988 170 28 13 Alumina600° C. 250° C. 69 NA NA NA NA NA NA NA 14 Alumina 600° C. 250° C. 48 00.9506 10.7 1466 4537 137 NA 15 Aluminophosphate (P/Al 0.9) 600° C. 250°C. 240 13.1 0.9570 2.8 352 2246 126 70 16 Aluminophosphate (P/Al 0.6) wF 600° C. 250° C. 563 6.21 0.9546 3.8 412 2573 109 61 17Aluminophosphate (P/Al 0.2) 600° C. 250° C. 157 0.596 0.9536 6.3 6583137 105 71 18 Si-Coated Alumina 400° C. 250° C. 204 0 0.9465 9.7 9063047 93.7 48 19 Si-Coated Alumina 600° C. 250° C. 646 0.004 0.9444 16.4856 2875 52.1 45 20 Si-Coated Alumina 800° C. 250° C. 1437 0 NA NA NA NANA 48 21 Si-Coated Alumina 800° C. 250° C. 1184 0.021 0.9459 12.6 7252668 57.8 61 22 F—Si-Coated Alumina 600° C. 150° C. 2935 0.273 0.946620.4 675 2516 33.0 80 23 F—Si-Coated Alumina 600° C. 250° C. 4496 0.0280.9478 14.3 652 2465 45.6 62 24 F—Si-Coated Alumina 600° C. 0.5% Cr,2680 0.060 0.9503 19.9 597 2212 29.9 85 250° C. 25 F—Si-Coated Alumina600° C. 250° C. 5205 0.075 0.9495 13.1 699 3049 53.3 65 26 F—Si-CoatedAlumina 600° C. 250° C. 3303 0.052 0.9484 10.2 701 2952 68.7 65 27F—Si-Coated Alumina 600° C. 250° C. 3174 0.117 NA NA NA NA NA 44 28SO₄/Alumina 1.6 mmol SO4/g 600° C. 150° C. 541 0.258 0.9504 19.4 7872918 40.6 60 29 SO₄/Alumina 1.6 mmol SO4/g 600° C. 250° C. 1072 0.4040.9517 8.5 662 3136 78.0 125 30 SO₄/Alumina 1.6 mmol SO4/g 600° C. 250°C. 1126 0.393 0.9526 6.7 692 3242 103 119 31 F—Si-Coated Ti-Alumina 600°C. 250° C. 2466 0.085 0.9477 5.3 664 2524 125 68 32 F-Silica-Alumina500° C. 250° C. 1220 5.556 0.9529 5.3 427 2617 81.1 29 33 Cl—F—Si-CoatedAlumina 600° C. 120° C. 5365 0.007 0.9492 5.74 725 2781 126.3 57 34Cl—F—Si-Coated Alumina 600° C. 120° C. 6734 0.09 NA 5.66 750 2888 132.544 35 Cr/silica - Cr(VI) 700° C. NA, Air 2166 4.31 0.9632 11.1 272 163824.6 138 36 Cr/alumina - Cr(VI) 600° C. NA, Air 372 13.8 0.9621 6.92 3573425 51.6 146 37 Cr/Si-Coated-Alumina - Cr(VI) 600° C. NA, Air 511 0.900.9592 18.3 511 3194 27.8 291

TABLE III Impact of Hydrogen Addition Mole % H₂ (based on Melt Index(MI, Supported Catalyst ethylene) g/10 min) Cr(VI)/Silica, 800° C. 00.55 0.2 0.72 0.5 0.98 1.0 1.15 Cr(AcAc)₃ on F—Si-Coated 0 0 Alumina0.41 2.3 0.82 18.5

This invention is described above with reference to numerous aspects andembodiments, and specific examples. Many variations will suggestthemselves to those skilled in the art in light of the above detaileddescription. All such obvious variations are within the full intendedscope of the appended claims. Other embodiments of the invention caninclude, but are not limited to, the following (embodiments aredescribed as “comprising” but, alternatively, can “consist essentiallyof” or “consist of”):

Embodiment 1. A process to produce a supported chromium catalyst, theprocess comprising:

(i) combining a chromium (III) compound (or trivalent chromium) with anactivator-support comprising a solid oxide treated with anelectron-withdrawing anion to form a mixture; and

(ii) subjecting (or exposing, or treating) the mixture to anon-oxidizing atmosphere at a peak temperature to produce the supportedchromium catalyst.

Embodiment 2. The process defined in embodiment 1, wherein the peaktemperature is in any peak temperature range disclosed herein, e.g.,from about 25° C. to about 600° C., from about 150° C. to about 350° C.,etc.

Embodiment 3. The process defined in embodiment 1 or 2, wherein the step(ii) is conducted for a time period in any range of time periodsdisclosed herein, e.g., from about 30 minutes to about 12 hours, fromabout 1 hour to about 6 hours, etc.

Embodiment 4. The process defined in any one of embodiments 1-3, whereinthe non-oxidizing atmosphere is any inert atmosphere disclosed herein,e.g., comprising nitrogen, neon, argon, a vacuum, etc., as well ascombinations thereof.

Embodiment 5. The process defined in any one of embodiments 1-3, whereinthe non-oxidizing atmosphere is any reducing atmosphere disclosedherein, e.g., comprising H₂, CO, etc., as well as combinations thereof.

Embodiment 6. The process defined in any one of embodiments 1-5, whereinstep (i) is conducted at a temperature in any temperature rangedisclosed herein, e.g., from about 0° C. to about 100° C., from about10° C. to about 50° C., etc.

Embodiment 7. The process defined in any one of embodiments 1-6, whereinstep (i) comprises dry mixing the activator-support with the chromium(III) compound, and step (ii) comprises subjecting the mixture to thenon-oxidizing atmosphere at a peak temperature sufficient for at least aportion of the chromium (III) compound to sublime (or vaporize) andimpregnate the activator-support.

Embodiment 8. The process defined in any one of embodiments 1-6, whereinstep (i) comprises mixing the activator-support with the chromium (III)compound in a solvent, and step (ii) comprises subjecting the mixture tothe non-oxidizing atmosphere at a peak temperature sufficient to removethe solvent.

Embodiment 9. catalyst composition comprising:

a supported chromium catalyst comprising (a) a chromium (III) compound,or a derivative thereof; and (b) an activator-support comprising a solidoxide treated with an electron-withdrawing anion; and

a co-catalyst.

Embodiment 10. The process or composition defined in any one ofembodiments 1-9, wherein the chromium (III) compound comprises anychromium (III) compound disclosed herein, e.g., a chromium (III)1,3-diketone compound, chromium (III) acetylacetonate, etc., or aderivative thereof; a compound containing only chromium, carbon,hydrogen, and oxygen atoms; not a chromium oxide or other chromiumcompound that does not contain a carbon atom; etc.

Embodiment 11. The process or composition defined in any one ofembodiments 1-9, wherein the chromium (III) compound comprises chromium(III) formate, chromium (III) acetate, chromium (III) propionate,chromium (III) butyrate, chromium (III) pentanoate, chromium (III)neopentanoate, chromium (III) hexanoate, chromium (III)2-ethylhexanoate, chromium (III) benzoate, chromium (III) naphthenate,chromium (III) oleate, chromium (III) oxalate, chromium (III)acetylacetonate, chromium (III) stearate, chromium (III) laurate, aderivative thereof, or a combination thereof.

Embodiment 12. The process or composition defined in any one ofembodiments 1-9, wherein the chromium (III) compound comprises chromium(III) 1,3-butanedionate, chromium (III) 2,4-hexanedionate, chromium(III) 2,4-heptanedionate, chromium (III) 2,4-octanedionate, chromium(III) 3,5-octanedionate, chromium (III) benzoylacetonate, chromium (III)1,3-diphenyl-1,3-propanedionate, chromium (III)2-methyl-1,3-butanedionate, chromium (III) 2-ethyl-1,3-butanedionate,chromium (III) 2-phenyl-1,3-butanedionate, chromium (III)1,2,3-triphenyl-1,3-propanedionate, chromium (III)2,2,6,6-tetramethylheptanedionate, a derivative thereof, or acombination thereof.

Embodiment 13. The process or composition defined in any one of thepreceding embodiments, wherein the solid oxide comprises any solid oxidedisclosed herein, e.g., alumina, silica-alumina, silica-coated alumina,aluminum phosphate, aluminophosphate, heteropolytungstate, titania,silica-titania, zirconia, silica-zirconia, magnesia, boria, zinc oxide,etc., as well as any mixed oxide thereof or any mixture thereof.

Embodiment 14. The process or composition defined in any one of thepreceding embodiments, wherein the solid oxide comprises alumina,silica-alumina, silica-coated alumina, or any mixture thereof.

Embodiment 15. The process or composition defined in any one of thepreceding embodiments, wherein the solid oxide comprises silica-aluminaor silica-coated alumina, either comprising silica in any range ofweight percentages disclosed herein, e.g., from about 10 to about 80 wt.% silica, from about 20 to about 70 wt. % silica, from about 25 to about50 wt. % silica, etc., based on the weight of the silica-alumina orsilica-coated alumina.

Embodiment 16. The process or composition defined in any one of thepreceding embodiments, wherein the electron-withdrawing anion comprisesany electron withdrawing anion disclosed herein, e.g., sulfate,bisulfate, fluoride, chloride, bromide, iodide, fluorosulfate,fluoroborate, phosphate, fluorophosphate, trifluoroacetate, triflate,fluorozirconate, fluorotitanate, phospho-tungstate, tungstate,molybdate, etc., as well as any combination thereof.

Embodiment 17. The process or composition defined in any one of thepreceding embodiments, wherein the electron-withdrawing anion comprisesfluoride and/or sulfate (or fluoride and/or chloride).

Embodiment 18. The process or composition defined in any one of thepreceding embodiments, wherein the activator-support comprises afluorided solid oxide and/or a sulfated solid oxide.

Embodiment 19. The process or composition defined in any one of thepreceding embodiments, wherein the activator-support comprises anyactivator-support disclosed herein, e.g., fluorided alumina, chloridedalumina, bromided alumina, sulfated alumina, fluorided silica-alumina,chlorided silica-alumina, bromided silica-alumina, sulfatedsilica-alumina, fluorided silica-zirconia, chlorided silica-zirconia,bromided silica-zirconia, sulfated silica-zirconia, fluoridedsilica-titania, fluorided silica-coated alumina, sulfated silica-coatedalumina, phosphated silica-coated alumina, chlorided/fluoridedsilica-coated alumina, etc., as well as combinations thereof.

Embodiment 20. The process or composition defined in any one of thepreceding embodiments, wherein the activator-support comprises fluoridedalumina, sulfated alumina, fluorided silica-alumina, sulfatedsilica-alumina, fluorided silica-coated alumina, sulfated silica-coatedalumina, or any combination thereof.

Embodiment 21. The process or composition defined in any one of thepreceding embodiments, wherein the weight percentage of chromium(present in the chromium (III) compound), based on the weight of theactivator-support, is in any weight percentage range disclosed herein,e.g., from about 0.1 to about 10 wt. %, from about 0.25 to about 5 wt.%, from about 0.5 to about 2 wt. %, etc.

Embodiment 22. The process or composition defined in any one of thepreceding embodiments, wherein the weight percentage of theelectron-withdrawing anion, based on the weight of theactivator-support, is in any range of weight percentages disclosedherein, e.g., from about 1 to about 20 wt. %, from about 2 to about 15wt. %, from about 3 to about 12 wt. %, etc.

Embodiment 23. The composition defined in any one of embodiments 9-22,wherein the catalyst composition comprises any co-catalyst disclosedherein.

Embodiment 24. The composition defined in any one of embodiments 9-23,wherein the catalyst composition comprises an aluminoxane co-catalyst,an organoaluminum co-catalyst, an organoboron co-catalyst, or anycombination thereof.

Embodiment 25. The composition defined in any one of embodiments 9-24,wherein the catalyst composition comprises an organoaluminum co-catalystcomprising trimethylaluminum, triethylaluminum, tri-n-propylaluminum,tri-n-butylaluminum, triisobutylaluminum, tri-n-hexylaluminum,tri-n-octylaluminum, diisobutylaluminum hydride, diethylaluminumethoxide, diethylaluminum chloride, or any combination thereof.

Embodiment 26. The composition defined in any one of embodiments 9-25,wherein the catalyst composition comprises an organoaluminum co-catalyst(e.g., triisobutylaluminum) in a organoaluminum:chromium molar ratiorange from about 10:1 to about 1000:1 (e.g., 100:1), and ischaracterized by a catalyst activity greater than 500 grams (or 1000grams) of ethylene polymer per gram of supported catalyst per hour,under slurry polymerization conditions, using isobutane as a diluent,and with a polymerization temperature of 100° C. and a reactor pressureof 550 psig.

Embodiment 27. The composition defined in any one of embodiments 9-26,further comprising a metallocene compound, e.g., any metallocenecompound disclosed herein, at a molar ratio of chromium to metal of themetallocene compound in any molar ratio range disclosed herein, e.g.,from about 1:20 to about 20:1, from about 5:1 to about 1:5, etc.

Embodiment 28. An olefin polymerization process, the process comprisingcontacting the catalyst composition defined in any one of embodiments9-27 with an olefin monomer and an optional olefin comonomer in apolymerization reactor system under polymerization conditions to producean olefin polymer.

Embodiment 29. The process defined in embodiment 28, wherein the olefinmonomer comprises any olefin monomer disclosed herein, e.g., any C₂-C₂₀olefin.

Embodiment 30. The process defined in embodiment 28 or 29, wherein theolefin monomer and the optional olefin comonomer independently comprisea C₂-C₂₀ alpha-olefin.

Embodiment 31. The process defined in any one of embodiments 28-30,wherein the olefin monomer comprises ethylene.

Embodiment 32. The process defined in any one of embodiments 28-31,wherein the catalyst composition is contacted with ethylene and anolefin comonomer comprising a C₃-C₁₀ alpha-olefin.

Embodiment 33. The process defined in any one of embodiments 28-32,wherein the catalyst composition is contacted with ethylene and anolefin comonomer comprising 1-butene, 1-hexene, 1-octene, or a mixturethereof.

Embodiment 34. The process defined in any one of embodiments 28-30,wherein the olefin monomer comprises propylene.

Embodiment 35. The process defined in any one of embodiments 28-34,wherein the polymerization reactor system comprises a batch reactor, aslurry reactor, a gas-phase reactor, a solution reactor, a high pressurereactor, a tubular reactor, an autoclave reactor, or a combinationthereof.

Embodiment 36. The process defined in any one of embodiments 28-35,wherein the polymerization reactor system comprises a slurry reactor, agas-phase reactor, a solution reactor, or a combination thereof.

Embodiment 37. The process defined in any one of embodiments 28-36,wherein the polymerization reactor system comprises a loop slurryreactor.

Embodiment 38. The process defined in any one of embodiments 28-37,wherein the polymerization reactor system comprises a single reactor.

Embodiment 39. The process defined in any one of embodiments 28-37,wherein the polymerization reactor system comprises 2 reactors.

Embodiment 40. The process defined in any one of embodiments 28-37,wherein the polymerization reactor system comprises more than 2reactors.

Embodiment 41. The process defined in any one of embodiments 28-40,wherein the olefin polymer comprises any olefin polymer disclosedherein.

Embodiment 42. The process defined in any one of embodiments 28-33 and35-41, wherein the olefin polymer is an ethylene/1-butene copolymer, anethylene/1-hexene copolymer, or an ethylene/1-octene copolymer.

Embodiment 43. The process defined in any one of embodiments 28-33 and35-41, wherein the olefin polymer is an ethylene/1-hexene copolymer.

Embodiment 44. The process defined in any one of embodiments 28-30 and34-41, wherein the olefin polymer is a polypropylene homopolymer or apropylene-based copolymer.

Embodiment 45. he process defined in any one of embodiments 28-44,wherein the polymerization conditions comprise a polymerization reactiontemperature in a range from about 60° C. to about 120° C. and a reactionpressure in a range from about 200 to about 1000 psig (about 1.4 toabout 6.9 MPa).

Embodiment 46. The process defined in any one of embodiments 28-45,wherein the polymerization conditions are substantially constant, e.g.,for a particular polymer grade.

Embodiment 47. The process defined in any one of embodiments 28-46,wherein no hydrogen is added to the polymerization reactor system.

Embodiment 48. The process defined in any one of embodiments 28-46,wherein hydrogen is added to the polymerization reactor system.

Embodiment 49. The process defined in embodiment 48, wherein an increasein the melt index of the olefin polymer with the addition of hydrogenfrom 0 to 1 mol % (based on the olefin monomer) is greater than theincrease in melt index obtained using a Cr(VI)/silica catalyst, underthe same polymerization conditions.

Embodiment 50. The process defined in embodiment 48, wherein a meltindex of an olefin polymer produced by the process in the presence of0.5 mol % hydrogen (based on the olefin monomer) is greater than themelt index of an olefin polymer obtained using a Cr(VI)/silica catalyst,under the same polymerization conditions.

Embodiment 51. The process defined in any one of embodiments 28-50,wherein a polymer defined in any one of embodiments 53-62 is produced.

Embodiment 52. An olefin polymer produced by the olefin polymerizationprocess defined in any one of embodiments 28-51.

Embodiment 53. An ethylene polymer having (I) a ratio of Mw/Mn ofgreater than or equal to about 35, or greater than or equal to about 50,or greater than equal to about 70, or greater than or equal to about 90;and (II) a Mw in a range from about 200,000 to about 2,000,000 g/mol, orfrom about 300,000 to about 1,000,000 g/mol, or from about 400,000 toabout 900,000 g/mol, or from about 500,000 to about 900,000 g/mol.

Embodiment 54. The polymer defined in embodiment 53, wherein theethylene polymer has a relaxation time in any range disclosed herein,e.g., less than or equal to about 500 sec, less than or equal to about100 sec, less than or equal to about 85 sec, less than or equal to about70 sec, etc.

Embodiment 55. The polymer defined in embodiment 53 or 54, wherein theethylene polymer has less than or equal to about 0.005 long chainbranches (LCB) per 1000 total carbon atoms, e.g., less than or equal toabout 0.002 LCB per 1000 total carbon atoms, less than or equal to about0.001 LCB per 1000 total carbon atoms, etc.

Embodiment 56. The polymer defined in any one of embodiments 53-55,wherein the ethylene polymer has a density in any range disclosedherein, e.g., from about 0.90 to about 0.97, from about 0.92 to about0.96, from about 0.93 to about 0.955, from about 0.94 to about 0.95g/cm³, etc.

Embodiment 57. The polymer defined in any one of embodiments 53-56,wherein the ethylene polymer has a conventional comonomer distribution,e.g., the number of short chain branches (SCB) per 1000 total carbonatoms of the polymer at Mn is greater than at Mz, the number of SCB per1000 total carbon atoms at Mn is greater than at Mw, etc.

Embodiment 58. The polymer defined in any one of embodiments 53-57,wherein the ethylene polymer has a melt index less than or equal toabout 100, less than or equal to about 10, less than or equal to about5, less than or equal to about 1 g/10 min, etc.

Embodiment 59. The polymer defined in any one of embodiments 53-58,wherein the ethylene polymer has a HLMI in any range disclosed herein,e.g., less than or equal to about 1000, less than or equal to about 100,less than or equal to about 10, less than or equal to about 5, less thanor equal to about 1 g/10 min, etc.

Embodiment 60. The polymer defined in any one of embodiments 53-59,wherein the ethylene polymer has a ratio of Mz/Mw in any range disclosedherein, e.g., from about 1.5 to about 10, from about 2 to about 8, fromabout 2 to about 6, from about 2 to about 5, etc.

Embodiment 61. The polymer defined in any one of embodiments 53-60,wherein the ethylene polymer has a Mn in any range disclosed herein,e.g., from about 2,000 to about 25,000, from about 2,000 to about20,000, from about 3,000 to about 19,000, from about 4,000 to about15,000 g/mol, etc.

Embodiment 62. The polymer defined in any one of embodiments 53-61,wherein the ethylene polymer has a Mz in any range disclosed herein,e.g., from about 1,000,000 to about 5,000,000, from about 1,500,000 toabout 4,000,000, from about 2,000,000 to about 3,500,000 g/mol, etc.

Embodiment 63. An article of manufacture comprising the polymer definedin any one of embodiments 52-62.

Embodiment 64. A method for forming or preparing an article ofmanufacture comprising an olefin polymer, the method comprising (i)performing the olefin polymerization process defined in any one ofembodiments 28-50 to produce the olefin polymer, and (ii) forming thearticle of manufacture comprising the olefin polymer defined in any oneof embodiments 52-62, e.g., via any technique disclosed herein.

Embodiment 65. The article defined in embodiment 63 or 64, wherein thearticle is an agricultural film, an automobile part, a bottle, a drum, afiber or fabric, a food packaging film or container, a food servicearticle, a fuel tank, a geomembrane, a household container, a liner, amolded product, a medical device or material, a pipe, a sheet or tape,or a toy.

We claim:
 1. An olefin polymerization process, the process comprising:(i) combining a chromium (III) compound with an activator-supportcomprising a solid oxide treated with an electron-withdrawing anion toform a mixture; (ii) subjecting the mixture to a non-oxidizingatmosphere at a peak temperature to produce a supported chromiumcatalyst; and (iii) contacting the supported chromium catalyst and aco-catalyst with ethylene and an optional olefin comonomer in apolymerization reactor system under polymerization conditions to producean ethylene polymer, wherein a molar ratio of co-catalyst:chromium is ina range from about 50:1 to about 500:1; and wherein the ethylene polymerhas a melt index in a range from 0 to about 0.5 g/10 min, and a Mw in arange from about 400,000 to about 900,000 g/mol.
 2. The process of claim1, wherein: an increase in melt index of the ethylene polymer producedby the process with the addition of hydrogen from 0 to 1 mol %, based onethylene, is greater than an increase in melt index of an ethylenepolymer obtained using a Cr(VI)/silica catalyst system, under the samepolymerization conditions; or a melt index of an ethylene polymerproduced by the process in the presence of 0.5 mol % hydrogen, based onethylene, is greater than a melt index of an ethylene polymer obtainedusing a Cr(VI)/silica catalyst system, under the same polymerizationconditions; or both.
 3. The process of claim 1, wherein: thepolymerization reactor system comprises a slurry reactor, gas-phasereactor, solution reactor, or a combination thereof; and the supportedchromium catalyst and the co-catalyst are contacted with ethylene and anolefin comonomer comprising 1-butene, 1-hexene, 1-octene, or a mixturethereof.
 4. The process of claim 1, wherein the ethylene polymer is anethylene/α-olefin copolymer characterized by a number of short chainbranches (SCB) per 1000 total carbon atoms at Mn that is greater than atMw.
 5. The process of claim 1, wherein the ethylene polymer ischaracterized by: a ratio of Mw/Mn in a range from about 90 to about200; and/or a HLMI of less than or equal to about 1 g/10 min; andwherein the ethylene polymer is an ethylene homopolymer, anethylene/1-butene copolymer, an ethylene/1-hexene copolymer, or anethylene/1-octene copolymer.
 6. The process of claim 1, wherein the peaktemperature is in a range from about 25° C. to about 600° C.
 7. Theprocess of claim 1, wherein the non-oxidizing atmosphere is an inertatmosphere.
 8. The process of claim 1, wherein step (i) comprises drymixing the activator-support with the chromium (III) compound, and step(ii) comprises subjecting the mixture to the non-oxidizing atmosphere ata peak temperature sufficient for at least a portion of the chromium(III) compound to sublime or vaporize and impregnate theactivator-support.
 9. The process of claim 1, wherein step (i) comprisesmixing the activator-support with the chromium (III) compound in asolvent, and step (ii) comprises subjecting the mixture to thenon-oxidizing atmosphere at a peak temperature sufficient to remove thesolvent.
 10. The process of claim 1, wherein: the chromium (III)compound comprises chromium (III) formate, chromium (III) acetate,chromium (III) propionate, chromium (III) butyrate, chromium (III)pentanoate, chromium (III) neopentanoate, chromium (III) hexanoate,chromium (III) 2-ethylhexanoate, chromium (III) benzoate, chromium (III)naphthenate, chromium (III) oleate, chromium (III) oxalate, chromium(III) acetylacetonate, chromium (III) stearate, chromium (III) laurate,or any combination thereof; and the activator-support comprisesfluorided alumina, chlorided alumina, bromided alumina, sulfatedalumina, fluorided silica-alumina, chlorided silica-alumina, bromidedsilica-alumina, sulfated silica-alumina, fluorided silica-zirconia,chlorided silica-zirconia, bromided silica-zirconia, sulfatedsilica-zirconia, fluorided silica-titania, fluorided silica-coatedalumina, sulfated silica-coated alumina, phosphated silica-coatedalumina, or any combination thereof.
 11. The process of claim 1,wherein: the chromium (III) compound comprises chromium (III)acetylacetonate; and the activator-support comprises a fluorided solidoxide and/or a sulfated solid oxide.
 12. The process of claim 1,wherein: a weight percentage of chromium, based on the weight of theactivator-support, is in a range from about 0.25 to about 5 wt %; and aweight percentage of the electron-withdrawing anion, based on the weightof the activator-support, is in a range from about 2 to about 15 wt %.13. The process of claim 1, wherein the co-catalyst comprises analuminoxane co-catalyst.
 14. The process of claim 1, wherein theco-catalyst comprises an organoaluminum co-catalyst.
 15. The process ofclaim 1, wherein: the chromium (III) compound comprises chromium (III)formate, chromium (III) acetate, chromium (III) propionate, chromium(III) butyrate, chromium (III) pentanoate, chromium (III) neopentanoate,chromium (III) hexanoate, chromium (III) 2-ethylhexanoate, chromium(III) benzoate, chromium (III) naphthenate, chromium (III) oleate,chromium (III) oxalate, chromium (III) acetylacetonate, chromium (III)stearate, chromium (III) laurate, a derivative thereof, or anycombination thereof; the activator-support comprises sulfated alumina,fluorided silica-alumina, fluorided silica-coated alumina, or anycombination thereof; and the co-catalyst comprises trimethylaluminum,triethylaluminum, tri-n-propylaluminum, tri-n-butylaluminum,triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum,diisobutylaluminum hydride, diethylaluminum ethoxide, diethylaluminumchloride, or any combination thereof.
 16. The process of claim 15,wherein the ethylene polymer is characterized by: a ratio of Mw/Mn in arange from about 90 to about 200; and/or a HLMI of less than or equal toabout 1 g/10 min; and wherein the ethylene polymer is an ethylenehomopolymer, an ethylene/1-butene copolymer, an ethylene/1-hexenecopolymer, or an ethylene/1-octene copolymer.
 17. The process of claim16, wherein greater than 500 grams of the ethylene polymer per gram ofthe supported chromium catalyst are produced per hour, under slurrypolymerization conditions, using isobutane as a diluent, with anorganoaluminum:chromium molar ratio of 100:1, and with a polymerizationtemperature of 100° C. and a reactor pressure of 550 psig.
 18. An olefinpolymerization process, the process comprising: (i) combining a chromium(III) compound with an activator-support comprising a solid oxidetreated with an electron-withdrawing anion to form a mixture; (ii)subjecting the mixture to a non-oxidizing atmosphere at a peaktemperature in a range from about 25° C. to about 250° C. to produce asupported chromium catalyst; and (iii) contacting the supported chromiumcatalyst and a co-catalyst with ethylene and an optional olefincomonomer in a polymerization reactor system under polymerizationconditions to produce from about 2000 to about 10,000 grams of theethylene polymer per gram of the supported chromium catalyst per hour;wherein the ethylene polymer has a melt index in a range from 0 to about0.5 g/10 min.
 19. The process of claim 18, wherein: the non-oxidizingatmosphere is an inert atmosphere; the polymerization reactor systemcomprises a slurry reactor, gas-phase reactor, solution reactor, or acombination thereof; and the supported chromium catalyst and theco-catalyst are contacted with ethylene and an olefin comonomercomprising 1-butene, 1-hexene, 1-octene, or a mixture thereof.
 20. Theprocess of claim 18, wherein: the chromium (III) compound compriseschromium (III) formate, chromium (III) acetate, chromium (III)propionate, chromium (III) butyrate, chromium (III) pentanoate, chromium(III) neopentanoate, chromium (III) hexanoate, chromium (III)2-ethylhexanoate, chromium (III) benzoate, chromium (III) naphthenate,chromium (III) oleate, chromium (III) oxalate, chromium (III)acetylacetonate, chromium (III) stearate, chromium (III) laurate, aderivative thereof, or any combination thereof; the activator-supportcomprises sulfated alumina, fluorided silica-alumina, fluoridedsilica-coated alumina, or any combination thereof; and the co-catalystcomprises trimethylaluminum, triethylaluminum, tri-n-propylaluminum,tri-n-butylaluminum, triisobutylaluminum, tri-n-hexylaluminum,tri-n-octylaluminum, diisobutylaluminum hydride, di ethylaluminumethoxide, diethylaluminum chloride, or any combination thereof.
 21. Theprocess of claim 18, wherein the ethylene polymer is characterized by: aratio of Mw/Mn in a range from about 90 to about 200; and/or a HLMI ofless than or equal to about 1 g/10 min.
 22. The process of claim 18,wherein: a weight percentage of chromium, based on the weight of theactivator-support, is in a range from about 0.25 to about 5 wt %; thechromium (III) compound comprises chromium (III) acetylacetonate; aweight percentage of the electron-withdrawing anion, based on the weightof the activator-support, is in a range from about 2 to about 15 wt %;and the activator-support comprises a fluorided solid oxide and/or asulfated solid oxide.
 23. The process of claim 18, wherein thepolymerization reactor system comprises a loop slurry reactor.
 24. Anolefin polymerization process, the process comprising: (i) combiningchromium (III) acetylacetonate with an activator-support comprising afluorided solid oxide and/or a sulfated solid oxide to form a mixture;(ii) subjecting the mixture to an inert atmosphere at a peak temperatureto produce a supported chromium catalyst; and (iii) contacting thesupported chromium catalyst and a co-catalyst with ethylene and anoptional olefin comonomer in a polymerization reactor system underpolymerization conditions to produce an ethylene polymer; wherein themolar ratio of co-catalyst:chromium is in a range from about 50:1 toabout 500:1; the polymerization reactor system comprises a loop slurryreactor, gas-phase reactor, solution reactor, or a combination thereof;and the ethylene polymer has a melt index in a range from 0 to about 0.5g/10 min, and a ratio of Mw/Mn in a range from about 35 to about 150.